See the v4.0.0 release notes for an overview of what’s new in 4.0.0. Use lodash-migrate, lodash-codemods, & eslint-plugin-lodash to help migrate pre-4 lodash code to the latest release.

Fixes a ReferenceError issue in lodash lodash-es lodash-amd and lodash.template when using the template and fromPairs functions from the modular builds. See https://github.com/lodash/lodash/issues/6167#issuecomment-4165269769

These defects were related to how lodash distributions are built from the main branch using https://github.com/lodash-archive/lodash-cli. When internal dependencies change inside lodash functions, equivalent updates need to be made to a mapping in the lodash-cli. (hey, it was ahead of its time once upon a time!). We know this, but we missed it in the last release. It's the kind of thing that passes in CI, but fails bc the build is not the same thing you tested.

There is no diff on main for this, but you can see the diffs for each of the npm packages on their respective branches:

• lodash: https://github.com/lodash/lodash/compare/4.18.0-npm...4.18.1-npm
• lodash-es: https://github.com/lodash/lodash/compare/4.18.0-es...4.18.1-es
• lodash-amd: https://github.com/lodash/lodash/compare/4.18.0-amd...4.18.1-amd
• lodash.templatehttps://github.com/lodash/lodash/compare/4.18.0-npm-packages...4.18.1-npm-packages

_.unset / _.omit: Fixed prototype pollution via constructor/prototype path traversal (GHSA-f23m-r3pf-42rh, fe8d32e). Previously, array-wrapped path segments and primitive roots could bypass the existing guards, allowing deletion of properties from built-in prototypes. Now constructor and prototype are blocked unconditionally as non-terminal path keys, matching baseSet. Calls that previously returned true and deleted the property now return false and leave the target untouched.

_.template: Fixed code injection via imports keys (GHSA-r5fr-rjxr-66jc, CVE-2026-4800, 879aaa9). Fixes an incomplete patch for CVE-2021-23337. The variable option was validated against reForbiddenIdentifierChars but importsKeys was left unguarded, allowing code injection via the same Function() constructor sink. imports keys containing forbidden identifier characters now throw "Invalid imports option passed into _.template".

• Add security notice for _.template in threat model and API docs (#6099)
• Document lower > upper behavior in _.random (#6115)
• Fix quotes in _.compact jsdoc (#6090)

Diff

We have also regenerated and published a select number of the lodash.* modular packages.

These modular packages had fallen out of sync significantly from the minor/patch updates to lodash. Specifically, we have brought the following packages up to parity w/ the latest lodash release because they have had CVEs on them in the past:

• lodash.orderby
• lodash.tonumber
• lodash.trim
• lodash.trimend
• lodash.sortedindexby
• lodash.zipobjectdeep
• lodash.unset
• lodash.omit
• lodash.template

• Fix prototype pollution in _.unset and _.omit functions (CVE-2025-13465)

• Prevent command injection through _.template's variable option
• Improve performance of toNumber, trim and trimEnd on large input strings

• Fixed issue with dependencies mapping
• Ensured modularized files in the lodash package are up to date

• Allowed _.sortedIndexBy methods to short-circuit for empty arrays
• Ensured _.orderBy accepts iteratee path arrays
• Ensured _.isEqual returns accurate results without depending on parameter order for circular references
• Sanitized sourceURL in _.template
• Fix prototype pollution bug in _.zipObjectDeep
• Note: releases of 4.17.16 to 4.17.18 of the lodash npm package were corrupted; please update to more recent versions

• Removed unintentionally published project helper scripts

• Reverted use of the "type" field in package.json of lodash-es

• Fixed missing dependency of _createRound

• Ensured _.ceil, _.floor, & _round handle Infinity consistently
• Ensured _.debounce clears old timers before starting new ones
• Ensured _.mergeWith always provides a stack to customizer
• Ensured additions to Object.prototype don’t break lodash initialization
• Ensured map and set clones contain custom properties of source values
• Fixed prototype pollution for _.defaultsDeep
• Fixed prototype pollution for _.template options

• Ensured _.merge handles function properties consistently regardless of number of sources
• Ensured Object.prototype is not augmented by _.merge
• Ensured placeholder properties are set on fp.convert() results
• Avoided ReDoS issue in _.words implementation

• Updated Lodash for better Node.js 10 support

• Ensured _.clone supports subclassed arrays
• Ensured _.cloneDeep works with cyclical maps & sets
• Ensured _.defaults avoids unnecessary source property access
• Ensured _.invert doesn’t error on inverted values without toString methods
• Ensured _.merge & _.mergeWith avoid augmenting __proto__ properties
• Ensured _.set supports paths with symbols
• Ensured _.words detects ordinals in compound words
• Ensured fp.update works with paths that refer to functions

• Ensured _.omit with deep paths doesn’t mutate object

• Added support for symbol properties to _.isEqual
• Ensured getSymbols helper only gets enumerable symbols
• Ensured _.startsWith avoids coercing position of undefined
• Flipped iteratee arguments for fp.reduceRight
• Removed the array length limit for lazy evaluation

• Ensured _.pick picks keys over paths
• Ensured _.spread doesn’t include arguments after those spread
• Fixed _.omit performance regression

• Ensured _.omit copies shallow path values by reference
• Ensured _.pick supports path arrays
• Ensured _.pickBy doesn’t treat keys with dots or brackets as deep paths

• Added deep path support to _.omit & _.pick
• Ensured fp.assignAllWith & fp.mergeAllWith accept more than two sources
• Made process.binding detection more cautious to avoid chatty debugging

• Ensured _.xor returns an empty array when comparing the same array

• Added support for ordinal numbers to _.words
• Ensured _.xor works with more than two arrays
• Ensuredfp.convert handles aliased & remapped methods
• Improved “fp” debugging
• Made “isType” methods resistant to toStringTag spoofing
• Made _.isEmpty exit early for nullish values
• Refined _.isError checks to avoid false positives for plain objects
• Simplified _.isElement

• Added support for buffers to _.transform
• Added support for typed arrays to _.isEmpty
• Ensured _.toString works on an array of symbols
• Fixed _.merge regression with buffers
• Normalized buffers & typed arrays keys in “keys” methods
• Split _.isArguments out for older & newer environments

• Added a _.runInContext check in the “fp” browser build
• Ensured _.defaultsDeep & _.merge consistently assign undefined values
• Fixed _.isFunction detection of Proxy in Safari 10
• Made _.isEqual treat buffers differently than Uint8Array values
• Removed es-sham requirement for older browsers

• Fixed _.sampleSize performance regression
• Made “clone” methods use newer Buffer APIs when available

• Fixed backtick removal of _.escape & _.unescape
• Improved parse time by 2x in V8

• Added fp.rangeStep & fp.rangeStepRight
• Added a cache limit to internal _.memoize use
• Avoided V8 de-opts in _.isElement, _.isObject, & _.isObjectLike
• Dropped backtick encoding from _.escape & _.unescape
• Dropped testing in Node.js 0.10 & 0.12
• Ensured __proto__ is treated as a regular key in assignments
• Fixed _.bind & _.partial performance regression
• Optimized _.concat

• Added Latin Extended-A block support to _.deburr
• Reduced dependencies of _.isEmpty & _.toNumber

• Ensured methods work with mocked Date.now, clearTimeout, & setTimeout
• Ensured paths of “set” methods overwrite primitives
• Ensured fp.nthArg returns a curried function
• Reduced dependencies of _.initial, _.merge, & _.tail
• Removed old JIT & engine bug guards

• Ensured paths with consecutive empty brackets or dots are parsed correctly
• Ensured _.random & “range” methods coerce arguments to finite numbers
• Fixed circular reference detection in _.cloneDeep
• Removed global prerequisite for exports detection

• Added _.conformsTo & _.defaultTo
• Added more “fp” aliases
• Added “All” variants of fp/assign, fp/defaults,fp/merge, & fp/zip methods
• Ensured debounced cancel uses clearTimeout
• Ensured the alias _.first supports shortcut fusion
• Ensured _.assignWith respects customizer results of undefined
• Ensured _.divide & _.multiply return 1 when no arguments are specified
• Ensured _.isEqual has transitive equivalence for circular references
• Fixed argument order of fp/zipObjectDeep
• Simplified resolving the global object
• Stopped unconditional global exports in the browser
• Made per method packages zero-dependency modules
• Made wrapped function toString results more debuggable
• Made “flatten” methods honor Symbol.isConcatSpreadable
• Made _.isEqual treat invalid dates as equivalent
• Made LARGE_ARRAY_SIZE check in stackSet align with others
• Optimized adding values to stacks by not inspecting all key-value pairs
• Optimized “isType” methods to use faster Node.js C++ helpers when available
• Optimized _.endsWith, _.negate, & _.startsWith

• Ensured _.find & _.findLast provide the correct key param when iterating objects

• Added _.stubArray, _.stubFalse, _.stubObject, _.stubString, & _.stubTrue
• Added fromIndex param to _.find, _.findIndex, _.findLast, & _.findLastIndex
• Ensured empty brackets & dots in paths are treated as empty property names
• Ensured _.pullAll works with the same value for array & values
• Ensured _.round works with large precision values
• Ensured _.throttle works with a system time of 0
• Made _.isNative throw if core-js is detected
• Simplified UMD exports
• Added fp/findFrom, fp/findIndexFrom, fp/findLastFrom, fp/findLastIndexFrom, fp/indexOfFrom, & fp/lastIndexOfFrom
• Fixed argument order of fp/differenceBy, fp/differenceWith, fp/intersectionBy, fp/intersectionWith, fp/without, fp/unionBy, fp/unionWith, fp/xorBy, & fp/xorWith

• Added _.toFinite
• Added iteratee arity hints to “forEach” methods
• Added support for maps & sets to _.toPairs & _.toPairsIn
• Ensured _.merge doesn’t skip trailing function sources
• Ensured fp/forEach, fp/forIn, & fp/forOwn cap their iteratee arguments
• Ensured fp/update does not convert end of path to an object
• Ensured matches methods match arrays with duplicate values
• Optimized “flatten” methods
• Simplified _.concat
• Updated cache implementations

• Ensured _.pullAt correctly sorts indexes greater than 9
• Ensured _.words doesn’t treat punctuation as words
• Ensured -0 works as path arguments
• Ensured set methods like _.uniq & _.xor convert -0 to 0

• Added fp/pluck as an alias of fp/map
• Ensured _.debounce defers invoking func when leading is false & wait is 0

• Added _.nth
• Added _.matchesProperty shorthand support to _.sortBy
• Added support for contractions to case methods & _.words
• Avoided unnecessary array cloning in createRecurryWrapper & mergeData
• Ensured fp/over doesn’t cap its iteratee arguments
• Made _.head avoid accessing array when its length is 0

• Added isIterateeCall check to _.split
• Added fp/paths & fp/props as aliases of fp/at
• Added fp/propEq as an alias of fp/matchesProperty
• Ensured _.debounce queues a trailing call for subsequent debounced calls after maxWait
• Ensured _.split handles a limit of 0 correctly in Node.js v0.10
• Optimized handling of emojis in string methods
• Removed fp/mapObj & fp/propOf aliases

• Added back _.matchesProperty shorthand support to “over” methods
• Ensured _.split works with emojis
• Fixed malformed fp/toString & fp/valueOf modules

• Reverted _.matchesProperty shorthand support for “over” methods

• Fixed typo in fp/_falseOptions

• Added fp/placeholder module & fp/__ alias
• Added convert to unconverted “fp” methods
• Added _.matchesProperty shorthand support to “over” methods
• Avoided errors in older Firefoxes when coercing Promise to a string
• Ensured _.has returns false for nested nullish object values
• Ensured _.has treats nested sparse arrays consistently
• Fixed argument order of fp/overArgs
• Made _.chunk, _.repeat, & _.sampleSize default n to 1 instead of 0
• Optimized _.matchesProperty shorthand

• Added _.divide, _.flatMapDeep, _.flatMapDepth, _.meanBy, & _.multiply
• Added fp/convert, fp/invokeArgs, fp/invokeArgsMap, fp/padChars, fp/padCharsEnd, fp/padCharsStart, fp/restFrom, & fp/spreadFrom
• Added _.entries as an alias of _.toPairs
• Added _.entriesIn as an alias of _.toPairsIn
• Added several “fp” aliases
• Added support for buffers to _.isEmpty
• Added support for maps & sets to _.isEmpty & _.size
• Added support for deep cloning data views, maps, & sets
• Added symbol support to _.omit, _.toNumber, & _.toPath
• Avoided a JIT bug in Safari 9 for baseIteratee
• Ensured array sequence methods don’t error for falsey values
• Ensured _.concat casts non-array array values to arrays
• Ensured _.has returns false for nested inherited properties
• Ensured _.isEqual compares promises by reference
• Ensured _.isPlainObject returns false for objects with a custom [[Prototype]]
• Ensured _.mergeWith sources are cloned when customizer returns undefined
• Ensured _.startCase only uppercases the first character of each word
• Ensured _.words detects words where an all caps word is next to a capitalized word
• Fixed argument order of fp/bind, fp/bindKey, & fp/isEqualWith
• Fixed aliases fp/all, fp/any, & fp/anyPass
• Made _.result resolve values of functions as it deep crawls over them
• Memoized stringToPath
• Optimized _.pad, _.padEnd, _.padStart, & _.toNumber
• Refactored _.debounce to simplify, reduce timers, & fix bugs

• Optimized baseClone to avoid cloning symbols for internal use

• Added _.pullAllWith, _.update, & _.updateWith
• Added core.min.js & lodash.min.js to the “fp” module ignored list
• Ensured _.defaultsDeep does not overwrite regexp values
• Ensured _.isEqual works with maps & sets with circular references
• Ensured “fp” uses lodash as the default placeholder
• Ensured stack is popped after a recursive merge so that it doesn’t affect sibling properties
• Fixed order of arguments in “fp” docs
• Optimized baseIsEqualDeep by removing a typed array check & unnecessary stack creation
• Optimized _.assign, _.assignIn, & _.intersection
• Optimized _.merge to avoid deep cloning sources if a customizer is provided
• Removed dead code from getNative
• Replaced Symbol checks with Symbol methods checks

• Added core.min.js & lodash.min.js to the npm package
• Ensured placeholders persist through more than one curried call
• Ensured assignValue assigns values if they aren’t the same own value
• Ensured “fp” methods avoid unnecessary cloning
• Ensured fp/omitBy & fp/pickBy provide value & key params to iteratees
• Fixed arity of fp/orderBy
• Used getPrototypeOf to set inheritance when constructor is a function

• Enabled support for cloning expando properties of boolean, number, & string objects
• Ensured fp/convert wrappers support iteratee shorthands

• Added _.castArray & _.flattenDepth
• Fixed argument order of fp/inRange & fp/zipWith
• Enabled fp/convert to auto wrap lodash in the browser
• Enabled fp/convert to work when given lodash with options
• Ensured fp/convert options works when applied individually
• Ensured fp/convert works with category modules
• Ensured _.isError works with subclassed values
• Ensured _.merge deep clones array, typed-array, & plain-object sources
• Ensured a debounced maxWait timeout isn’t processed on a leading call when leading is false & there isn’t a max delay queued

• Added _.isArrayBuffer, _.isBuffer, _.isMap, _.isSet, _.isWeakMap, & _.isWeakSet
• Added options param to fp/convert
• Ensured default placeholder values are set for relevant method modules
• Ensured _.add & _.subtract return 0 when no arguments are given
• Ensured fp/gt, fp/gte, fp/lt, & fp/lte don’t have rearg applied
• Improved accuracy of _.debounce & _.throttle

• Added remap of fp/trim as fp/trimChars for chars param support
• Ensured wrapped _.bind, _.curry, & _.partial support placeholders
• Ensured fp/_baseConvert uses _.spread for _.partial wrapper
• Ensured fp/add & fp/subtract don’t have rearg applied

• Added fp/assoc & fp/assocPath as aliases of fp/set
• Added fp/dissoc & fp/dissocPath as aliases of fp/unset
• Added start param to _.spread
• Ensured _.attempt preserves custom errors
• Ensured fp/partial & fp/partialRight accept an args param
• Ensured fp/unset is immutable
• Ensured _.iteratee clones sources for _.matchesProperty shorthand
• Made _.flatMap a “Collection” method
• Removed global references from the npm package

• Added _.invertBy & _.zipObjectDeep
• Added cherry pickable “fp” method modules to the npm package
• Ensured fp/convert works with aliases
• Ensured _.clone & _.cloneDeep work on prototype objects
• Ensured _.mergeWith overwrites primitives with source object clones
• Ensured _.sum & _.sumBy return 0 for empty arrays
• Optimized _.isEmpty for objects
• Fixed argument order of fp/assign, fp/defaults, & fp/merge

• Added _.matches to the core build
• Added placeholder support to “fp” methods
• Added support for keycap emojis
• Ensured _.concat returns an empty array for nullish values
• Ensured _.each & _.eachRight aliases have the correct chain behavior
• Ensured _.defaultsDeep doesn’t convert function properties to objects
• Ensured _.fromPairs can consume results of _.toPairs
• Ensured _.isEqual compares objects unordered
• Ensured _.noConflict restores _ only if lodash is the current value
• Ensured _.words captures all-caps words
• Ensured _.words treats all-lower & all-upper postfixes as separate words
• Fixed “fp” mapping of several methods
• Made _.omitBy & _.pickBy provide a key param to iteratees

• Removed Bower & Component package support in favor of npm

• Dropped IE 6-8 support

• Use es5-shim, & optionally es6-shim, to enable support

• Made _#times, _#forEach, _#forIn, _#forOwn, & their right-forms implicitly end chain sequences

var wrapped = _([1, 2, 3]);

// in 3.10.1
wrapped.forEach(function(n) { console.log(n); });
// ➜ returns the lodash wrapper without logging until `value` is called
wrapped.forEach(function(n) { console.log(n); }).value();
// ➜ logs each value from left to right and returns the array

// in 4.0.0
wrapped.forEach(function(n) { console.log(n); });
// ➜ logs each value from left to right and returns the array

• Removed category names from module paths

 // in 3.10.1
 var chunk = require('lodash/array/chunk');

 // in 4.0.0
 var chunk = require('lodash/chunk');

• Removed _.pluck in favor of _.map with iteratee shorthand

var objects = [{ 'a': 1 }, { 'a': 2 }];

// in 3.10.1
_.pluck(objects, 'a'); // ➜ [1, 2]
_.map(objects, 'a'); // ➜ [1, 2]

// in 4.0.0
_.map(objects, 'a'); // ➜ [1, 2]

• Removed thisArg params from most methods because they were largely unused, complicated implementations, & can be tackled with _.bind, Function#bind, or arrow functions

 var objects = [{ 'a': 1 }, { 'a': 2 }];
 var context = { 'b': 5 };

 function callback(item) {
   return item.a + this.b;
 }

 // in 3.10.1
 _.map(objects, callback, context);

 // in 4.0.0
 _.map(objects, _.bind(callback, context));

• Split _.max & _.min into _.maxBy & _.minBy

var array = [1, 2, 3],
    objects = [{ 'a': 1 }, { 'a': 2 }];

// in 3.10.1
_.max(array); // ➜ 3
_.max(objects, 'a'); // ➜ { 'a': 2 }

_.min(array); // ➜ 1
_.min(objects, 'a'); // ➜ { 'a': 1 }

// in 4.0.0
_.max(array); // ➜ 3
_.maxBy(objects, 'a'); // ➜ { 'a': 2 }

_.min(array); // ➜ 1
_.minBy(objects, 'a'); // ➜ { 'a': 1 }

• Method removals
  • Removed _.support
  • Removed _.findWhere in favor of _.find with iteratee shorthand
  • Removed _.where in favor of _.filter with iteratee shorthand
  • Removed _.pluck in favor of _.map with iteratee shorthand
• Method renames
  • Renamed _.first to _.head
  • Renamed _.indexBy to _.keyBy
  • Renamed _.invoke to _.invokeMap
  • Renamed _.modArgs to _.overArgs
  • Renamed _.padLeft & _.padRight to _.padStart & _.padEnd
  • Renamed _.pairs to _.toPairs
  • Renamed _.rest to _.tail
  • Renamed _.restParam to _.rest
  • Renamed _.sortByOrder to _.orderBy
  • Renamed _.trimLeft & _.trimRight to _.trimStart & _.trimEnd
  • Renamed _.trunc to _.truncate
• Split out methods
  • Split _.assign & _.assignIn into _.assignWith & _.assignInWith
  • Split _.clone & _.cloneDeep into _.cloneWith & _.cloneDeepWith
  • Split _.indexOf & _.lastIndexOf into _.sortedIndexOf & _.sortedLastIndexOf
  • Split _.invert into _.invertBy (see v4.1.0)
  • Split _.isEqual into _.isEqualWith
  • Split _.isMatch into _.isMatchWith
  • Split _.max & _.min into _.maxBy & _.minBy
  • Split _.merge into _.mergeWith
  • Split _.omit & _.pick into _.omitBy & _.pickBy
  • Split _.sample into _.sampleSize
  • Split _.sortedIndex into _.sortedIndexBy
  • Split _.sortedLastIndex into _.sortedLastIndexBy
  • Split _.sum into _.sumBy
  • Split _.uniq into _.sortedUniq, _.sortedUniqBy, & _.uniqBy
  • Split _.zipObject into _.fromPairs
• Absorbed _.sortByAll into _.sortBy
• Changed the category of _.at to “Object”
• Changed the category of _.bindAll to “Util”
• Changed _.matchesProperty shorthand to an array of [path, srcValue]
• Enabled _.merge to assign undefined if the destination property doesn’t exist
• Made “By” methods like _.groupBy & _.sortBy provide a single param to iteratees
• Made _.add, _.max, _.min, & _.sum no longer coerce values to numbers
• Made _.capitalize uppercase the first character & lowercase the rest (see _.upperFirst)
• Made _.eq its own method instead of an alias for _.isEqual
• Made _.functions return only own method names
• Made _.max & _.min return undefined when passed an empty array
• Made _.words chainable by default
• Moved ./lodash.js to ./dist/lodash.js in the master branch
• Moved ./index.js to ./lodash.js in the npm branch
• Removed isDeep params from _.clone & _.flatten
• Removed multiValue param from _.invert
• Removed support for binding all methods by default from _.bindAll
• Removed func-first param signature from _.before & _.after

• Dropped boolean options param support in _.debounce, _.mixin, & _.throttle
• Dropped support for boolean orders param in _.orderBy
• Made _.escapeRegExp align to the defunct ES7 proposal
• Made _.max, _.min, & _.sum support arrays only
• Removed legacy options param signature from _.template

• Core build

  • 4 kB (gzipped) core build (64 methods; Backbone ≥ v1.3.0 compatible)
    _.assignIn, _.before, _.bind, _.chain, _.clone, _.compact, _.concat, _.create, _.defaults, _.defer, _.delay, _.each, _.escape, _.every, _.filter, _.find, _.first, _.flatten, _.flattenDeep, _.forEach, _.has, _.head, _.identity, _.indexOf, _.isArguments, _.isArray, _.isBoolean, _.isDate, _.isEmpty, _.isEqual, _.isFinite, _.isFunction, _.isNaN, _.isNull, _.isNumber, _.isObject, _.isRegExp, _.isString, _.isUndefined, _.iteratee, _.keys, _.last, _.map, _.matches, _max, _.min, _.mixin, _.negate, _.noConflict, _.noop, _.once, _.pick, _.reduce, _.result, _.size, _.slice, _.some, _.sortBy, _.tap, _.thru, _.toArray, _.uniqueId, _#value, & _.values
  • Reduced functionality:
    • Cloning only supports arrays & Object objects
    • Iteratee shorthand for _.matchesProperty is removed
    • Lazy evaluation is removed
    • Placeholder support is removed
    • Support for deep property paths is removed
    • Support for maps, sets, & typed arrays is removed

• Added 80 methods

  • 22 array methods:
    _.concat, _.differenceBy, _.differenceWith, _.fromPairs, _.intersectionBy, _.intersectionWith, _.join, _.pullAll, _.pullAllBy, _.reverse, _.sortedIndexBy, _.sortedIndexOf, _.sortedLastIndexBy, _.sortedLastIndexOf, _.sortedUniq, _.sortedUniqBy, _.unionBy, _.unionWith, _.uniqBy, _.uniqWith, _.xorBy, & _.xorWith

  • 18 lang methods:
    _.cloneDeepWith, _.cloneWith, _.eq, _.isArrayLike, _.isArrayLikeObject, _.isEqualWith, _.isInteger, _.isLength, _.isMatchWith, _.isNil, _.isObjectLike, _.isSafeInteger, _.isSymbol, _.toInteger, _.toLength, _.toNumber, _.toSafeInteger, & _.toString

  • 13 object methods:
    _.assignIn, _.assignInWith, _.assignWith, _.functionsIn, _.hasIn, _.invoke, _.mergeWith, _.omitBy, _.pickBy, _.setWith, _.toPairs, _.toPairsIn, & _.unset

  • 8 string methods:
    _.lowerCase, _.lowerFirst, _.replace, _.split, _.upperCase, _.upperFirst, _.toLower, & _.toUpper

  • 8 utility methods:
    _.cond, _.conforms, _.nthArg, _.over, _.overEvery, _.overSome, _.rangeRight, & _.toPath

  • 4 math methods:
    _.maxBy, _.mean, _.minBy, & _.sumBy

  • 2 collection methods:
    _.flatMap (see v4.2.0) & _.sampleSize

  • 2 function methods:
    _.flip & _.unary

  • 2 number methods:
    _.clamp & _.subtract

  • 1 chain method:
    _#next

• Added 3 aliases

  • Added _.extend as an alias of _.assignIn
  • Added _.extendWith as an alias of _.assignInWith
  • Added _.first as an alias of _.head

• Removed 17 aliases

  • Removed _.all in favor of _.every
  • Removed _.any in favor of _.some
  • Removed _.backflow in favor of _.flowRight
  • Removed _.callback in favor of _.iteratee
  • Removed _.collect in favor of _.map
  • Removed _.compose in favor of _.flowRight
  • Removed _.contains in favor of _.includes
  • Removed _.detect in favor of _.find
  • Removed _.foldl in favor of _.reduce
  • Removed _.foldr in favor of _.reduceRight
  • Removed _.include in favor of _.includes
  • Removed _.inject in favor of _.reduce
  • Removed _.methods in favor of _.functions
  • Removed _.object in favor of _.fromPairs or _.zipObject
  • Removed _#run in favor of _#value
  • Removed _.select in favor of _.filter
  • Removed _.unique in favor of _.uniq instead

• Performance improvements

  • Enabled shortcut fusion for _.at, _.find & _.findLast
  • Optimized match methods to avoid deep crawling if object & source identical
  • Optimized circular reference searches
  • Optimized _.isEqual to avoid stack crawls when arrays or objects are different sizes

• Emoji support

  • Added support for astral symbols, combining diacritical marks, dingbats, regional indicator symbols, unicode modifiers, variation selectors, & zero-width-joiners to string methods

• Functional goodies

  • Added _.cond, _.conforms, _.flip, _.nthArg, _.over, _.overEvery, _.overSome, & _.unary
  • Moved lodash-fp into lodash as require('lodash/fp') for immutable auto-curried iteratee-first data-last methods

• Added clear method to _.memoize.Cache
• Added flush method to debounced & throttled functions
• Added support for maps, sets, & symbols to _.clone, _.isEqual, & _.toArray
• Added support for array buffers to _.isEqual
• Added support for converting iterators to _.toArray
• Added support for deep paths to _.zipObject
• Changed UMD to export to window or self when available regardless of other exports
• Enabled _.flow & _.flowRight to accept an array of functions
• Ensured “Collection” methods treat functions as objects
• Ensured debounce cancel clears args & thisArg references
• Ensured _.add & _.sum don’t skip NaN values
• Ensured _.assign, _.defaults, & _.merge coerce object values to objects
• Ensured _.bindKey bound functions call object[key] when called with the new operator
• Ensured _.clone treats generators like functions
• Ensured _.clone produces clones with the source’s [[Prototype]]
• Ensured _.defaults assigns properties that shadow Object.prototype
• Ensured _.defaultsDeep doesn’t merge a string into an array
• Ensured _.defaultsDeep & _.merge don’t modify sources
• Ensured _.defaultsDeep works with circular references
• Ensured _.isFunction returns true for generator functions
• Ensured _.keys skips “length” on strict mode arguments objects in Safari 9
• Ensured _.merge assigns typed arrays directly
• Ensured _.merge doesn’t convert strings to arrays
• Ensured _.merge merges plain-objects onto non plain-objects
• Ensured _#plant resets iterator data of cloned sequences
• Ensured _.random swaps min & max if min is greater than max
• Ensured _.range preserves the sign of start of -0
• Ensured _.reduce & _.reduceRight use getIteratee in their array branch
• Fixed rounding issue with the precision param of _.floor
• Made _(...) an iterator & iterable
• Made _.drop, _.take, & right forms coerce n of undefined to 0

• Ensured func is a function before calling getData
• Ensured _.clone provides the correct number of arguments to customizer
• Ensured _#reverse doesn’t modify the original array when called after _#slice

• Added _.ceil, _.defaultsDeep, _.floor, _.modArgs, & _.round
• Ensured _.bind works with all built-in constructors
• Ensured _#concat treats sparse arrays as dense
• Ensured _.chunk floors size values
• Ensured _.debounce & _.throttle reset lastCall after cancelling
• Ensure _.flow & _.flowRight work with functions combined with _.first
• Ensured _.indexOf returns -1 for unmatched binary searches
• Ensured _.noConflict operates on root & not context
• Made _.escapeRegExp more robust
• Made _.sortByOrder support orders of “asc” & “desc”
• Optimized _.flatten, _.max, & _.min
• Removed fallbacks for _.isArguments, _.isFunction, & _.isPlainObject
• Simplified lazy evaluation support
• Simplified _.isElement, _.isFinite, _.isNative, _.now, _.parseInt, & _.sum

• Made parseFloat assigned from the context param of _.runInContext
• Ensured _.set handles non-index property names that start with numbers correctly

• Made isLaziable work with wrapped lodash methods
• Optimized an early exit case in _.isEqual
• Optimized _.sample

• Added _.gt, _.gte, _.lt, & _.lte
• Added support for an ImmutableMap to _.memoize.Cache
• Avoided using require in source comments to improve browserify build times
• Ensured baseCreate works in ExtendScript
• Ensured customizer results are respected by _.isEqual
• Ensured LodashWrapper.prototype.thru exists before creating a wrapper in flow
• Ensured _.bind works with ES2015 class constructors
• Ensured _.get can return null values
• Ensured _.intersection works with a single array
• Ensured _.has treats sparse arrays as dense
• Ensured _.merge skips undefined array values if a destination value exists
• Made null sort behind undefined & NaN
• Made _.eq an alias of _.isEqual
• Optimized object comparisons in _.isEqual
• Optimized _.max & _.min when invoked with iteratees
• Optimized _.pullAt & _.remove
• Used hasOwnProperty for the creation of reIsNative to avoid issues with core-js

• Added _.mapKeys, _.unzipWith, & _.zipWith
• Made _.difference, _.intersection, _.uniq, & _.xor accept array-like values
• Ensured empty brackets are ignored by _.get & _.set
• Ensured baseAt, basePullAt, & pullAt handle nullish values
• Ensured baseGet only returns undefined for incomplete paths
• Ensured _.padLeft & _.padRight handle empty strings correctly
• Made _.isEqual treat -0 & 0 as equivalent
• Narrowed bitmask checks in _.flow & _.flowRight
• Optimized lazy slice for start of 0
• Optimized “flatten” methods
• Restricted Object.assign use to strict mode only

• Added _.get, _.method, _.methodOf, & _.set
• Avoided a JIT bug in Safari on at least iOS 8.1-8.3 ARM64
• Ensured _.intersection of a single array returns an empty array
• Ensured _.remove mutates array after the predicate pass
• Ensured methods like _.has & _.get can access index values of strings
• Made createAssigner & _.sortByAll use _.restParam
• Made _.add coerce augend & addend params to numbers
• Made _.assign use built-in Object.assign when available
• Made _.inRange swap start & end params when start is greater than end
• Added deep path support to methods like _.has, _.get, _.callback, _.invoke, _.matchesProperty, _.method, _.methodOf, _.property, _.propertyOf, _.result, & _.set

• Added _.restParam
• Added isIterateeCall guards to _.every, _.includes, & _.some
• Added support for iteratee & thisArg params to _.sum
• Added support for shortcut fusion optimizations to _.flow & _.flowRight
• Ensured lodash bundled by r.js runs in a web worker
• Ensured _.deburr removes combining diacritical marks
• Ensured _.difference is based on the values of the first param only
• Expanded metadata optimizations to more combinations of curried functions
• Made _.matches work with non-plain objects & match inherited properties
• Optimized _.findLast, _.reduce, & _.reduceRight
• Reduced code duplication with internal method creator functions

• Added string replace & split chaining methods
• Ensured lazy drop works when applied after filter
• Optimized curried method performance

• Added _.add, _.sortByOrder, & _.sum
• Adjusted root to work when bundled by webpack & running in a web worker
• Ensured lazy chaining works with combinations of drop & dropWhile
• Ensured _.defaults works as an iteratee for _.reduce
• Reduced side effects of shortcut fusion
• Optimized baseFlatten, baseIndexOf, indexOfNaN, _.flow, & _.flowRight
• Optimized lazy evaluation for iteratees with one param

• Ensured lazy takeWhile works with lazy reverse & last
• Ensured wait defaults to 0 for _.debounce & _.throttle
• Ensured isIterateeCall doesn’t error if index is missing a toString method
• Optimized _.difference, _.intersection, & _.uniq in Firefox

• Added _.inRange
• Added links to each method’s npm package to the documentation
• Enabled _.clone to work with more truthy isDeep values
• Ensured each lodash wrapper module sets up their inheritance
• Ensured isIterateeCall works with NaN values
• Ensured _.merge avoids iterating string object or source params
• Optimized _.attempt
• Reduced nested dependencies of _.template

• Added _.fill, _.matchesProperty, & _.spread
• Added _#commit & _#plant
• Added support for lazy _.compact & _.toArray
• Enabled _.attempt to provide additional arguments to func
• Ensured _.flow returns an identity function when called without arguments
• Ensured _#reverse tracks __chain__ values
• Ensured lazy _.slice handles floating-point start & end params
• Fixed lazy _.slice when used after _.filter
• Made _#run an alias of _#value

• Added _.startCase
• Ensured isIterateeCall works correctly with objects

• Ensured _.slice coerces floating-point start & end params to integers
• Fixed lazy initial, rest, & reverse
• Fixed _.merge regression with DOM elements

• Made chaining lazy, that is, execution is deferred until _#value is implicitly or explicitly called

var wrapped = _([1, 2, 3]);

// in 2.4.1
wrapped.forEach(function(n) { console.log(n); });
// ➜ logs each value from left to right and returns the lodash wrapper

// in 3.0.0
wrapped.forEach(function(n) { console.log(n); });
// ➜ returns the lodash wrapper without logging until `value` is called
wrapped.forEach(function(n) { console.log(n); }).value();
// ➜ logs each value from left to right and returns the array

• Ensured each segment of a chain sequence may be repeatly applied

var array = [1],
    wrapped = _(array);

// in 2.4.1
var a = wrapped.push(2), // pushes `2` to `array`
    b = wrapped.push(3); // pushes `3` to `array`

a.value(); // ➜ returns `array`; [1, 2, 3]
b.value(); // ➜ returns `array`; [1, 2, 3]

// in 3.0.0
var a = wrapped.push(2), // creates a lazy sequence to push `2` to `array`
    b = wrapped.push(3); // creates a lazy sequence to push `3` to `array`

a.value(); // ➜ pushes `2` to `array` and returns `array`; [1, 2]
b.value(); // ➜ pushes `3` to `array` and returns `array`; [1, 2, 3]
a.value(); // ➜ pushes `2` to `array` and returns `array`; [1, 2, 3, 2]
b.value(); // ➜ pushes `3` to `array` and returns `array`; [1, 2, 3, 2, 3]

// use `_#commit` to commit a sequence and continue chaining
var a = wrapped.push(2).commit(), // pushes `2` to `array`
    b = wrapped.push(3).commit(); // pushes `3` to `array`

a.value(); // ➜ returns `array`; [1, 2, 3]
b.value(); // ➜ returns `array`; [1, 2, 3]

• Made _.flatten shallow by default & remove callback support

var array = [1, [[2], 3]],
    objects = [{ 'a': [1] }, { 'a': [2, 3] }];

// in 2.4.1
_.flatten(array); // ➜ [1, 2, 3]
_.flatten(objects, 'a'); // [1, 2, 3]

// in 3.0.0
_.flatten(array); // ➜ [1, [2], 3]
_.flattenDeep(array); // ➜ [1, 2, 3]
_(objects).pluck('a').flatten().value(); // [1, 2, 3]

• Removed the data parameter from _.template

var string = '<%= o.a %>',
    options = { 'variable': 'o' },
    data = { 'a': 'b' };

// in 2.4.1
_.template(string, data, options); // ➜ 'b'

// in 3.0.0
_.template(string, options)(data); // ➜ 'b'

• Split _.first & _.last into _.take, _.takeWhile, _.takeRight, & _.takeRightWhile

var array = [1, 2, 3],
    lessThanTwo = function(value) { return value < 2; },
    greaterThanTwo = function(value) { return value > 2; };

// in 2.4.1
_.first(array); // ➜ 1
_.first(array, 2); // ➜ [1, 2]
_.first(array, lessThanTwo);   // ➜ [1]

_.last(array); // ➜ 3
_.last(array, 2); // ➜ [2, 3]
_.last(array, greaterThanTwo); // ➜ [3]

// in 3.0.0
_.first(array); // ➜ 1
_.take(array, 2); // ➜ [1, 2]
_.takeWhile(array, lessThanTwo); // ➜ [1]

_.last(array); // ➜ 3
_.takeRight(array, 2); // ➜ [2, 3]
_.takeRightWhile(array, greaterThanTwo); // ➜ [3]

• Split _.initial & _.rest into _.dropRight, _.dropRightWhile, _.drop, & _.dropWhile

var array = [1, 2, 3],
    lessThanTwo = function(value) { return value < 2; },
    greaterThanTwo = function(value) { return value > 2; };

// in 2.4.1
_.initial(array); // ➜ [1, 2]
_.initial(array, 2); // ➜ [1]
_.initial(array, greaterThanTwo); // ➜ [1, 2]

_.rest(array); // ➜ [2, 3]
_.rest(array, 2); // ➜ [3]
_.rest(array, lessThanTwo); // ➜ [2, 3]

// in 3.0.0
_.initial(array); // ➜ [1, 2]
_.dropRight(array, 2); // ➜ [1]
_.dropRightWhile(array, greaterThanTwo); // ➜ [1, 2]

_.rest(array); // ➜ [2, 3]
_.drop(array, 2); // ➜ [3]
_.dropWhile(array, lessThanTwo); // ➜ [2, 3]

• Aligned _.isFinite & _.keys with ES2015
• Changed the category of _.clone & _.cloneDeep, & “isType” methods from “Object” to “Lang”
• Changed the category of _.escape, _.template, & _.unescape from “Util” to “String”
• Changed the category of _.range from “Array” to “Util”
• Changed the category of _.toArray from “Collection” to “Lang”
• Made method categories singular
• Made “Object” methods coerce primitives to objects
• Made _.clone & _.cloneDeep return a new object for unsupported types
• Made _.findWhere its own method instead of an alias for _.find
• Made _.max & _.min non-chainable by default
• Made _.memoize caches have the Map interface of delete, get, has, & set
• Made _.unzip its own method instead of an alias for _.zip
• Moved ./dist/lodash.js to ./lodash.js in the master branch
• Moved ./dist/lodash.js to ./lodash.js in the npm branch
• Moved ./dist/lodash.compat.js to the lodash/lodash-compat repository
• Moved support for sorting by multiple properties from _.sortBy to _.sortByAll
• Removed result sorting from _.functions
• Removed the underscore build
• Renamed _.createCallback to _.callback
• Renamed _.support.argsClass to _.support.argsTag
• Renamed _.support.nodeClass to _.support.nodeTag
• Restricted _.mixin to iterating only own properties of source objects
• Expanded the number of arguments provided to customizer callbacks of _.assign,
  _.clone, _.cloneDeep, _.isEqual, & _.merge

• Added customizable argument placeholder support to _.bind, _.bindKey, _.curry, _.curryRight, _.partial, & _.partialRight
• Added support for matching NaN to _.difference, _.includes, _.indexOf, _.intersection, _.lastIndexOf, _.union, _.uniq, & _.xor
• Ensured _.assign & _.merge don’t assign customizer results if it’s unchanged
• Ensured _.mixin doesn’t extend lodash when given an empty options object
• Ensured _.sortedIndex returns values that align with the sort order of _.sortBy
• Ensured functions of _.matches return true when comparing empty sources
• Ensured functions of _.matches perform own property checks on objects
• Made _.chain use an existing wrapper if available instead of creating a new wrapper
• Removed the argCount parameter from _.callback

• Added 47 methods

• 17 string methods:
  _.camelCase, _.capitalize, _.deburr, _.endsWith, _.escapeRegExp, _.kebabCase, _.pad, _.padLeft, _.padRight, _.repeat, _.snakeCase, _.startsWith, _.trim, _.trimLeft, _.trimRight, _.trunc, & _.words

• 11 array methods:
  _.chunk, _.dropRight, _.dropRightWhile, _.dropWhile, _.flattenDeep, _.pullAt, _.slice, _.sortedLastIndex, _.takeRight, _.takeRightWhile, & _.takeWhile

• 6 function methods:
  _.ary, _.before, _.curryRight, _.flow, _.negate, & _.rearg

• 5 lang methods:
  _.isError, _.isMatch, _.isNative, _.isTypedArray, & _.toPlainObject

• 3 utility methods:
  _.attempt, _.matches, & _.propertyOf

• 2 collection methods:
  _.partition & _.sortByAll

• 2 object methods:
  _.keysIn & _.valuesIn

• 1 chain method:
  _.thru

• Added 5 aliases

• Added _.backflow & _.compose as aliases of _.flowRight
• Added _.contains as an alias of _.includes
• Added _.iteratee as an alias of _.callback
• Added _#toJSON as an alias of _#valueOf

• Performance improvements

• Improved overall performance 20-40%
• Method chaining supports lazy evaluation
• Methods with support for shortcut fusion:
  _.drop, _.dropRight, _.dropRightWhile, _.dropWhile, _.filter, _.first, _.initial, _.last, _.map, _.pluck, _.reject, _.rest, _.reverse, _.slice, _.take, _.takeRight, _.takeRightWhile, _.takeWhile, & _.where
• Other optimized methods:
  _.bind, _.clone, _.cloneDeep, _.compact, _.compose, _.contains, _.difference, _.escape, _.flatten, _.invoke, _.isEqual, _.isObject, _.matches, _.max, _.min, _.partial, _.shuffle, _.unescape, _.uniq, _.without, & _.zip

• Functional goodies

• Added _.ary, _.curryRight, _.flow, & _.rearg
• Added placeholder support to _.bind, _.bindKey, _.curry, _.curryRight, _.partial, & _.partialRight
• Methods that work as an iteratee for _.map, & the like, out of the box:
  _.ary, _.callback, _.chunk, _.clone, _.create, _.curry, _.curryRight, _.drop, _.dropRight, _.flatten, _.invert, _.max, _.min, _.parseInt, _.slice, _.sortBy, _.take, _.takeRight, _.template, _.trim, _.trimLeft, _.trimRight, _.trunc, _.random, _.range, _.sample, _.uniq, & _.words
• Methods that work as an iteratee for _.reduce, & the like, out of the box:
  _.assign, _.defaults, _.merge, & _.sortAllBy

• Added cherry pickable method modules to the npm package
• Added cancel method to debounced & throttled functions
• Added defaultValue param to _.result
• Added multiValue param to _.invert
• Added thisArg param to _.tap
• Added _.memoize.Cache to enable Map/WeakMap to be used
• Added support for cloning array buffers & typed arrays to _.clone & _.cloneDeep
• Added support for comparing error objects & typed arrays to _.isEqual
• Enabled the sourceURL option of _.template to work in production builds
• Ensured _.at, _.matches, & _.pullAt work with falsey values when keys are given
• Ensured _.callback doesn’t error when func is nullish & thisArg is given
• Ensured _.callback supports binding built-in methods
• Ensured _.debounce & _.throttle work if the system time is set backwards
• Ensured _.difference works with arrays regardless of argument position
• Ensured _.findWhere & _.where always use _.matches
• Ensured _.includes supports fromIndex when iterating objects
• Ensured _.indexOf([], undefined, true) returns -1 instead of 0
• Ensured _.intersection ignores non-array secondary values
• Ensured _.isEqual works with wrapped objects containing constructor properties
• Ensured _.keys treats sparse arrays as dense
• Ensured _.keys works with string objects in IE < 9
• Ensured _.matches comparison isn’t affected by changes to source objects
• Ensured _.max & _.min return the correct value when callback computes ±Infinity
• Ensured _.merge ignores undefined values of source object properties
• Ensured _.partial & _.partialRight work with curried functions
• Ensured _.pluck always uses _.property
• Ensured _.random returns 1 or 0 when called with no arguments
• Ensured _.range, _.slice, & other methods handle NaN arguments
• Ensured _.runInContext uses a zeroed _.uniqueId counter
• Ensured _.transform checks that object is an object before using its [[Prototype]]
• Ensured _.where handles source objects with undefined property values
• Ensured _.where only returns elements that contain all source array/object values
• Ensured browserified lodash works in web workers
• Ensured customizing _.indexOf affects _.includes when iterating objects
• Ensured lodash works in NW.js
• Ensured lodash doesn’t add Function.prototype extensions to its prototype
• Fixed _.isFunction for typed array constructors in Safari 8
• Made _.escape & _.unescape handle backticks
• Made _.isElement more robust
• Made _.parseInt more closely follow spec
• Made _.wrap use _.identity when wrapper is nullish
• Made templates avoid referencing _.escape if “escape” delimiters are not used
• Made array-like object checks follow ES2015 ToLength
• Made use of Set in _.difference, _.intersection, & _.uniq
• Removed array & object pools
• Removed all method compilation from the compat build
• Updated the sourceURL syntax used by _.template

• Avoided memory leaks in _.bind, _.bindKey, _.curry, _.partial, & _.partialRight

• Ensured __bindData__ is properly cloned
• Ensured _.isEqual can compare cyclical objects with shared property values
• Optimized _.partial & _.partialRight
• Reached ~100% code coverage

• Added _.constant, _.mapValues, _.now, _.property, & _.xor
• Added an options param to _.mixin to specify whether functions added are chainable
• Added support for _.sortBy to accept an array of property names to sort by
• Enabled _.zipObject to accept an array of keys with no values param
• Removed conditional setImmediate use from _.defer

• Added _.create & _.noop
• Avoided memory leaks in _.debounce & _.throttle
• Enhanced _.createCallback to avoid binding functions bound by Function#bind
• Ensured rebound functions correctly partially apply arguments
• Ensured _.isEqual works with values from Object.create(null) & _(false)
• Ensured _.min & _.max work as callbacks for _.map
• Ensured _.template coerces the text param to a string
• Optimized _.difference, _.omit, & _.without by way of baseDifference
• Optimized _.isBoolean, _.isNumber, & _.isString for the false case
• Optimized _.sample & _.shuffle by way of baseRandom
• Reduced _.wrap by way of createBound
• Removed native Function#bind use for better cross-environment consistency

• Ensured _.mixin creates functions that work with _.chain
• Ensured the the createObject fallback is included in the modern build

• Added _.clone support for date, regexp, & other built-in objects
• Ensured _.random avoids excessive results of 0 for floating-point numbers
• Made compat & underscore builds use Date.now when available
• Reduced dependencies on getObject & releaseObject

• Added Object.defineProperty fallback for the modern build
• Added support to _.random to explicitly specify floating point numbers
• Enabled _.compose to be invoked without arguments
• Ensured _.flatten works with extremely large arrays
• Ensured _.support properties aren’t minified
• Ensured reThis isn’t used in Windows 8 applications
• Made UMD more resistant to false positives
• Optimized _.isArguments & _.isArray fallbacks

• Aligned _.after with Underscore 1.5.0, making it always return a function
• Made _.unzip an alias of _.zip

• Created lodash methods as npm packages & AMD/Node.js modules
• Made _.chain force chaining for all methods
• Moved the build utility to lodash-cli
• Optimized _.contains, _.debounce, _.isArguments, _.throttle, & _.where
• Optimized functions of _.bind, _.bindKey, _.curry, _.partial, & _.partialRight
• Added _.curry, _.forEachRight, _.indexBy, _.findLast, _.findLastIndex, _.findLastKey, _.forInRight, _.forOwnRight, _.pull, _.remove, & _.sample

• Added Curl & Dojo module loaders to the unit tests
• Added the modularize build option
• Added support for the iife command to be used without an %output% token
• Added support for _.mixin to accept a destination object
• Added support for _.range to accept a step of 0
• Ensured “Array” methods support arguments objects
• Ensured “Function” methods throw on non-functions
• Ensured _.at works as a callback for _.map
• Ensured _.createCallback works when no argCount is specified
• Ensured _.first & _.last return arrays when given an n with a falsey array
• Ensured _.flatten works with arguments objects
• Ensured minified files work with Dojo’s builder
• Ensured _.zipObject skips falsey elements
• Improved dead code removal from builds
• Improved JSDoc syntax
• Made _.eachRight an alias of _.forEachRight
• Made _.memoize avoid prefixing cache keys when using a resolver function
• Removed local clearTimeout & setTimeout variables from the underscore build
• Reduced the size of the repo & npm package
• Simplified the bailout in createCache
• Updated sourceURL & sourceMappingURL syntax
• Updated underscore build compatibility to v1.5.2

• Added missing cache property to the objects returned by getObject
• Ensured maxWait unit tests pass in Ringo
• Increased the maxPoolSize value
• Optimized releaseArray & releaseObject

• Added _.transform
• Added _.chain & _.findWhere aliases
• Added internal array & object pooling
• Added Istanbul test coverage reports to Travis CI
• Added maxWait option to _.debounce
• Added support for floating point numbers to _.random
• Added Volo configuration to package.json
• Adjusted UMD for component build
• Enabled more stable mixing of lodash & underscore build methods
• Ensured debounced function with leading & trailing options works as expected
• Ensured minified builds work with the Dojo builder
• Ensured minification avoids deoptimizing expressions containing boolean values
• Ensured support for --output paths containing build command keywords
• Ensured unknown types return false in _.isObject & _.isRegExp
• Ensured _.clone, _.flatten, & _.uniq can be used as callback for _.map
• Ensured _.forIn works on objects with longer inheritance chains in IE < 9
• Ensured _.isPlainObject returns true for empty objects in IE < 9
• Ensured _.max & _.min chain correctly
• Ensured clearTimeout use doesn’t cause errors in Titanium
• Ensured that the --stdout build option doesn’t write to a file
• Exposed memoized function’s cache
• Fixed Error.prototype iteration bugs
• Fixed “scripts” paths in component.json
• Made methods support customizing _.indexOf
• Made the build track dependencies of private functions
• Made the template pre-compiler build option avoid escaping non-ascii characters
• Made _.createCallback avoid binding functions if they don’t reference this
• Optimized the Closure Compiler minification process
• Optimized the large array cache for _.difference, _.intersection, & _.uniq
• Optimized internal _.flatten & _.indexOf use
• Reduced _.unzip & _.zip
• Removed special handling of arrays in _.assign & _.defaults

• Added Component package support
• Updated the build utility to work with changes in GitHub’s API
• Ensured _.isPlainObject works with objects created by Object.create(null)
• Ensured “isType” methods return false for subclassed values
• Ensured debounced functions, with leading & trailing calls enabled, only perform trailing calls after they’re called more than once

• Added _.unzip
• Added an options param to _.debounce & _.throttle
• Enabled non-underscore builds to include _.findWhere & _.chain
• Ensured “Array” & “Object” methods work with arguments objects & arrays respectively
• Ensured build utility runs on Windows
• Ensured underscore build versions of “isType” methods align with Underscore
• Ensured methods avoid issues with the __proto__ property
• Ensured _.isEqual uses a callback only if it’s a function
• Ensured _.merge applies a callback to nested properties
• Ensured _.merge provides the correct callback arguments when comparing objects
• Made lodash work with Browserify
• Removed all method compilation from the modern build

• Ensured the underscore build of _.forEach accepts a thisArg param
• Updated vendor/tar to work with Node.js v0.10

• Added _.createCallback, _.findIndex, _.findKey, _.parseInt, & _.runInContext
• Added _.support
• Added callback & thisArg params to _.flatten
• Added rhino -require support
• Added CommonJS/Node.js support to precompiled templates
• Ensured the exports object is not a DOM element
• Ensured _.isPlainObject returns false for objects without a [[Class]] of “Object”
• Made callback support in _.cloneDeep more closely follow its documentation
• Made _.object an alias of _.zipObject
• Made the template precompiler create missing directories of --output paths
• Optimized method chaining, object iteration, _.find, & _.pluck
• Updated backbone build method dependencies

• Ensured _.isPlainObject works when built-in Object.getPrototypeOf is unavailable

• Added support for specifying source map URLs in -p/--source-map options
• Ensured the second argument to _.assign is not treated as a callback
• Ensured -p/--source-map build options correctly set the sourceMappingURL
• Made -p/--source-map set source map “sources” keys based on the build
• Made _.defer use setImmediate, in Node.js, when available
• Made _.where search arrays for values regardless of their index position
• Removed dead code from _.template

• Made _.defaults preserve null values, instead of overwriting them

• Added _.at & _.partialRight
• Added modern & -p/--source-map build options
• Added “imports” option to _.templateSettings
• Added support for _.pluck & _.where callback shorthands
• Ensured _.assign & _.defaults support arrays
• Ensured _.merge assigns null values & produces dense arrays
• Deferred minifier downloads until the lodash utility requires them
• Flipped noNodeClass test to avoid Firebug’s “break on all errors” feature
• Made _.where support deep object comparisons
• Optimized _.invert, _.pairs, & _.values
• Reduced _.max, _.min, _.pluck, _.toArray, & _.where
• Removed support for automatic with-statement removal from _.template
• Simplified createIterator & iteratorTemplate
• Tweaked _.uniqueId to avoid problems with buggy minifiers
• Updated underscore build compatibility to v1.4.4
• Added callback & thisArg params to _.assign, _.clone, _.cloneDeep, _.first, _.last, _.initial, _.isEqual, _.merge, & _.rest

• Made _#join, _#pop, & _#shift wrapper methods return unwrapped values
• Made “Function” methods wrapper counterparts return wrapped values
• Removed “chain” methods

• Added _.cloneDeep
• Added _.once to the backbone build
• Ensured backbone builds implement Underscore’s chaining behavior
• Ensured the settings=… build option doesn’t clobber the default moduleId
• Ensured lodash’s npm package works when packages aren’t globally installed
• Made compiled templates exported for AMD use the lodash module for _
• Removed the _.forEach dependency from _.intersection
• Optimized _.isArray & _.isFunction fallbacks as well as _.intersection, _.isDate, _.isRegExp, _.reduce, _.reduceRight, _.union, & _.uniq

• Specified more method chaining behaviors
• Updated underscore build compatibility to v1.4.3

• Added support for arguments objects to _.clone
• Ensured _.clone creates plain object clones of non-plain objects
• Made _(…) chain automatically without needing to call _#chain
• Made _.isEqual equate arguments objects to similar Object objects

• Ensure lodash runs in the JS engine embedded in Adobe products
• Ensured _.reduce & _.reduceRight provide the correct callback arguments
• Ensured _.throttle nulls the timeoutId
• Made deep _.clone more closely follow the structured clone algorithm
• Optimized compiled templates in Firefox
• Optimized _.forEach, _.forOwn, _.isNumber, & _.isString
• Simplified iteratorTemplate

• Renamed _.lateBind to _.bindKey
• Made _.defaults & _.extend iterate only own properties of source objects to align with Object.assign

• Added the build commands used to custom build copyright/license headers
• Added _.assign
• Ensured the underscore build of _.find returns the first match, not last
• Ensured _.defaults, _.extends, & _.merge work with _.reduce
• Made lodash’s npm package installation work with more system configurations
• Made _.extend an alias of _.assign
• Optimized _.contains, _.defaults, _.extend, & _.filter
• Restricted _.where to iterate only own properties of source objects
• Updated backbone build lodash method dependencies

• Added fromIndex param to _.contains
• Added moduleId build option
• Added Closure Compiler “simple” optimizations to the build process
• Added support for strings in _.max & _.min
• Added support for ES2015 template delimiters to _.template
• Ensured re-minification of lodash by third parties avoids Closure Compiler bugs
• Optimized _.every, _.find, _.some, & _.uniq

• Ensured _.every returns false as soon as the callback result is falsey
• Ensured _.isFinite returns false for non-numeric values
• Removed _.forEach chainability in the underscore build
• Simplified _.union

• Added a sourceURL option to _.template
• Ensured _.where returns an empty array if given an empty properties object
• Expanded _.isFinite to return true for numeric strings
• Reduced _.intersection, _.omit, _.pick, _.sortedIndex, & _.where
• Reduced the npm package size by only downloading minifiers for global installs
• Reduced lodash’s file size
• Improved source code comprehension by removing compilation from _.bindAll, _.contains, _.countBy, _.every, _.filter, _.find, _.functions, _.groupBy, _.invert, _.invoke, _.isEmpty, _.map, _.merge, _.omit, _.pairs, _.pick, _.pluck, _.reduce, _.reject, _.some, _.sortBy, _.values, _.where, & internal shimKeys

• Ensured _.map returns an array when given a falsey collection
• Ensured _.throttle clears its timeout when func is called
• Made _.max, _.min, _.shuffle support iterating objects
• Reduced createIterator, _.clone, _.compact
• Re-optimized _.max, _.min, & _.sortedIndex

• Enabled deep clone support in the underscore build when clone is explicitly included
• Reverted removal of first argument falsey checks from methods

• Made _.random return 0 or 1 when no arguments are given
• Moved late bind functionality from _.bind to _.lateBind
• Removed first argument falsey checks from methods
• Removed support for custom clone, isEqual, toArray methods from _.clone, _.isEqual, & _.toArray

• Added -d/--debug, -m/--minify, minus, plus, settings, & template build options
• Added _.isPlainObject & _.lateBind
• Enabled _.sortedIndex to accept a property name as the callback param
• Ensured methods accept a thisArg of null
• Fixed the iife build option to accept more values
• Made _.times return an array of callback results
• Simplified _.max, _.min, & _.reduceRight

• Renamed _.zipObject to _.object
• Replaced _.drop with _.omit
• Made _.drop an alias of _.rest

• Added _.invert, _.pairs, & _.random
• Added _.result to the backbone build
• Added exports, iife, -c/--stdout, -o/--output, & -s/--silent build options
• Ensured isPlainObject works with objects from other documents
• Ensured _.isEqual compares values with circular references correctly
• Ensured _.merge work with four or more arguments
• Ensured _.sortBy performs a stable sort for undefined values
• Ensured _.template works with “interpolate” delimiters containing ternary operators
• Ensured the production build works in Node.js
• Ensured template delimiters are tokenized correctly
• Made pseudo private properties _chain & _wrapped double-underscored to avoid conflicts
• Made minify.js support underscore.js
• Reduced the size of mobile & underscore builds
• Simplified _.isEqual & _.size

• Ensured IE conditional compilation isn’t enabled by the useSourceURL test
• Optimized isPlainObject

• Added callback & thisArg params to _.drop & _.pick
• Added hasObjectSpliceBug test to avoid delete operator use
• Added _.unescape
• Ensured _.reduce works with string objects in IE < 9
• Made _.omit an alias of _.drop
• Made compiled methods take advantage of engines with strict mode optimizations
• Optimized _.intersection & removed its dependency on _.every
• Reduced the file size of the underscore build

• Ensured _.isElement uses strict equality for its duck type check
• Ensured _.isObject returns a boolean value
• Ensured _.template & “Object” methods don’t error when given falsey values
• Made _.template generate less unused code in compiled templates

• Ensured _.bind correctly appends array arguments to partially applied arguments in older browsers

• Added _.countBy, _.drop, _.merge, & _.where
• Added csp (Content Security Policy) & underscore build options
• Added deep cloning support to _.clone
• Added Jam package support
• Added support for exiting early in _.forEach, _.forIn, & _.forOwn
• Added support for jQuery/MooTools DOM query collections to _.isEmpty & _.size
• Ensured development build works with IE conditional compilation enabled
• Ensured _.clone doesn’t clone arguments objects, DOM nodes, functions, or non-plain objects
• Ensured _.filter’s callback can’t modify result values
• Ensured _.isEmpty, _.isEquals, & _.size support arguments objects
• Ensured _.isEqual doesn’t inspect DOM nodes, works with objects from other documents, & calls custom isEqual methods before checking strict equality
• Ensured _.once frees the given function for garbage collection
• Ensured _.sortBy performs a stable sort
• Ensured reEvaluateDelimiter is used when _.templateSettings.evaluate is undefined
• Made _.range coerce arguments to numbers
• Optimized _.isFunction

• Added strict build option
• Ensured _.bindAll, _.defaults, & _.extend avoid strict mode errors on read-only properties
• Optimized the iteration of large arrays in _.difference, _.intersection, & _.without
• Fixed build bugs related to removing variables

• Fixed _.template regression
• Optimized build process to detect & remove more unused variables

• Added bin & scripts entries to package.json
• Added legacy build option
• Added cross-browser support for strings to “Collection” methods
• Added _.zipObject
• Leveraged _.indexOf’s fromIndex in _.difference & _.without
• Optimized compiled templates
• Optimized inlining the iteratorTemplate for builds
• Optimized object iteration for “Collection” methods
• Optimized partially applied _.bind in V8
• Made compiled templates more debuggable
• Made _.size work with falsey values & consistent cross-browser with arguments objects
• Moved _.groupBy & _.sortBy back to the “Collection” category
• Removed arguments object from _.range

• Ensured _.escape returns an empty string for nullish values
• Ensured sourceURL support doesn’t cause errors in Adobe’s JS engine
• Fixed regression in generating custom builds
• Moved _.invoke & _.pluck back to the “Collection” category
• Moved _.tap to the “Seq” category

• Added backbone build option
• Ensured “Array” methods allow falsey array params
• Removed _.isArguments fallback from the mobile build
• Simplified _.pluck, _.values & _(...) method wrappers

• Added _.forIn & _.forOwn
• Added category build option
• Added fromIndex param to _.indexOf & _.lastIndexOf
• Added //@ sourceURL support to _.template
• Added thisArg param to _.sortedIndex & _.uniq
• Ensured array-like objects with invalid length properties are treated like regular objects
• Ensured _.sortedIndex supports arrays with high length values
• Fixed prototype iteration bug in _.keys
• Optimized _.times & this bindings in iterator methods

• Added mobile build option
• Ensured _.find returns undefined for unmatched values
• Ensured _.templateSettings.variable is compatible with Underscore
• Optimized _.escape
• Reduced dependencies of _.find

• Adjusted the lodash export order for r.js
• Ensured _.groupBy values are added to own, not inherited, properties
• Made _.bind follow ES5 spec to support a popular Backbone.js pattern
• Removed the alias _.intersect
• Simplified _.bind, _.flatten, _.groupBy, _.max, & _.min

• Added _.partial
• Added thisArg param to _.groupBy
• Added “lazy bind” support to _.bind
• Added custom build options
• Added default _.templateSettings.variable value
• Added native method overwrite detection to avoid bad native shims
• Added support for more AMD build optimizers & aliasing as the “underscore” module
• Added whitespace to compiled strings
• Commented the iterationFactory options object
• Ensured _(...) returns given wrapper instances
• Ensured _.max & _.min support extremely large arrays
• Ensured _.throttle works in tight loops
• Fixed clearTimeout typo
• Fixed [DontEnum] bug in IE < 9
• Fixed prototype iteration bug in Firefox < 3.6, Opera < 11.60, & Safari < 5.1
• Inlined _.isFunction calls
• Made _.debounce’ed functions match _.throttle’ed functions’ return value behavior
• Made _.escape no longer translate the “>” character
• Simplified all “Array” methods
• Optimized _.debounce, _.escape, _.flatten, _.forEach, _.groupBy, _.intersection, _.invoke, _.isObject, _.max, _.min, _.pick, _.shuffle, _.sortedIndex, _.template, _.throttle, _.union, _.uniq

• Initial release