pub mod no_floating_classes;

declare_lint_group! { pub Nursery { name : "nursery" , rules : [self :: no_ambiguous_anchor_text :: NoAmbiguousAnchorText , self :: no_before_interactive_script_outside_document :: NoBeforeInteractiveScriptOutsideDocument , self :: no_continue :: NoContinue , self :: no_deprecated_imports :: NoDeprecatedImports , self :: no_div_regex :: NoDivRegex , self :: no_duplicate_enum_values :: NoDuplicateEnumValues , self :: no_duplicated_spread_props :: NoDuplicatedSpreadProps , self :: no_empty_source :: NoEmptySource , self :: no_equals_to_null :: NoEqualsToNull , self :: no_excessive_lines_per_file :: NoExcessiveLinesPerFile , self :: no_floating_classes :: NoFloatingClasses , self :: no_floating_promises :: NoFloatingPromises , self :: no_for_in :: NoForIn , self :: no_import_cycles :: NoImportCycles , self :: no_increment_decrement :: NoIncrementDecrement , self :: no_jsx_literals :: NoJsxLiterals , self :: no_jsx_props_bind :: NoJsxPropsBind , self :: no_leaked_render :: NoLeakedRender , self :: no_misused_promises :: NoMisusedPromises , self :: no_multi_assign :: NoMultiAssign , self :: no_multi_str :: NoMultiStr , self :: no_next_async_client_component :: NoNextAsyncClientComponent , self :: no_parameters_only_used_in_recursion :: NoParametersOnlyUsedInRecursion , self :: no_proto :: NoProto , self :: no_react_forward_ref :: NoReactForwardRef , self :: no_return_assign :: NoReturnAssign , self :: no_script_url :: NoScriptUrl , self :: no_shadow :: NoShadow , self :: no_sync_scripts :: NoSyncScripts , self :: no_ternary :: NoTernary , self :: no_undeclared_env_vars :: NoUndeclaredEnvVars , self :: no_unknown_attribute :: NoUnknownAttribute , self :: no_unnecessary_conditions :: NoUnnecessaryConditions , self :: no_unresolved_imports :: NoUnresolvedImports , self :: no_unused_expressions :: NoUnusedExpressions , self :: no_useless_catch_binding :: NoUselessCatchBinding , self :: no_useless_undefined :: NoUselessUndefined , self :: no_vue_data_object_declaration :: NoVueDataObjectDeclaration , self :: no_vue_duplicate_keys :: NoVueDuplicateKeys , self :: no_vue_options_api :: NoVueOptionsApi , self :: no_vue_reserved_keys :: NoVueReservedKeys , self :: no_vue_reserved_props :: NoVueReservedProps , self :: no_vue_setup_props_reactivity_loss :: NoVueSetupPropsReactivityLoss , self :: use_array_sort_compare :: UseArraySortCompare , self :: use_await_thenable :: UseAwaitThenable , self :: use_consistent_arrow_return :: UseConsistentArrowReturn , self :: use_destructuring :: UseDestructuring , self :: use_error_cause :: UseErrorCause , self :: use_exhaustive_switch_cases :: UseExhaustiveSwitchCases , self :: use_explicit_type :: UseExplicitType , self :: use_find :: UseFind , self :: use_inline_script_id :: UseInlineScriptId , self :: use_max_params :: UseMaxParams , self :: use_qwik_method_usage :: UseQwikMethodUsage , self :: use_qwik_valid_lexical_scope :: UseQwikValidLexicalScope , self :: use_regexp_exec :: UseRegexpExec , self :: use_sorted_classes :: UseSortedClasses , self :: use_spread :: UseSpread , self :: use_vue_consistent_define_props_declaration :: UseVueConsistentDefinePropsDeclaration , self :: use_vue_define_macros_order :: UseVueDefineMacrosOrder , self :: use_vue_multi_word_component_names :: UseVueMultiWordComponentNames ,] } }

use biome_analyze::{

Ast, Rule, RuleDiagnostic, RuleSource, context::RuleContext, declare_lint_rule,

use biome_console::markup;

use biome_js_syntax::{JsNewExpression, JsSyntaxKind};

use biome_rowan::{AstNode, SyntaxNodeOptionExt};

use biome_rule_options::no_floating_classes::NoFloatingClassesOptions;

declare_lint_rule! {

/// Disallow `new` operators outside of assignments or comparisons.

///

/// The goal of using `new` with a constructor is typically to create an object of a particular type and store that object in a variable, such as:

///

/// ```js

/// const person = new Person();

/// ```

///

/// It's less common to use `new` and not store the result, such as:

///

/// ```js,ignore

/// new Person();

/// ```

///

/// In this case, the created object is thrown away because its reference isn't stored anywhere, and in many cases, this means that the constructor should be replaced with a function that doesn't require `new` to be used.

///

/// ## Examples

///

/// ### Invalid

///

/// ```js,expect_diagnostic

/// new Thing();

/// ```

///

/// ### Valid

///

/// ```js

/// const thing = new Thing();

/// ```

///

pub NoFloatingClasses {

version: "next",

name: "noFloatingClasses",

language: "js",

recommended: false,

sources: &[RuleSource::Eslint("no-new").same()],

}

impl Rule for NoFloatingClasses {

type Query = Ast<JsNewExpression>;

type State = ();

type Signals = Option<Self::State>;

type Options = NoFloatingClassesOptions;

fn run(ctx: &RuleContext<Self>) -> Self::Signals {

let node = ctx.query();

node.syntax()

.parent()

.kind()

.is_some_and(|kind| kind == JsSyntaxKind::JS_EXPRESSION_STATEMENT)

.then_some(())

}

fn diagnostic(ctx: &RuleContext<Self>, _state: &Self::State) -> Option<RuleDiagnostic> {

let node = ctx.query();

Some(

RuleDiagnostic::new(

rule_category!(),

node.range(),

markup! {

"Using the `new` operator outside of assignments or comparisons is not allowed."

},

)

.note(markup! {

"The created object is thrown away because its reference isn't stored anywhere. Assign the object to a variable or replace with a function that doesn't require `new` to be used."

}),

)

}

new Date()

source: crates/biome_js_analyze/tests/spec_tests.rs

expression: invalid.js

# Input

# Diagnostics

var a = new Date()

var a;

if (a === new Date()) {

a = false;

source: crates/biome_js_analyze/tests/spec_tests.rs

expression: valid.js

# Input