prettier · josephfrazier · Nov 8, 2017 · Sep 3, 2017 · Sep 6, 2017 · Sep 6, 2017
diff --git a/docs/configuration.md b/docs/configuration.md
@@ -83,3 +83,11 @@ For more information on how to use the CLI to locate a file, see the [CLI](cli.m
 ## Configuration Schema
 
 If you'd like a JSON schema to validate your configuration, one is available here: http://json.schemastore.org/prettierrc.
+
+## EditorConfig
+
+If an [`.editorconfig` file](http://editorconfig.org/) is in your project, Prettier will parse it and convert its properties to the corresponding prettier configuration. This configuration will be overridden by `.prettierrc`, etc. Currently, the following EditorConfig properties are supported:
+
+* `indent_style`
+* `indent_size`/`tab_width`
+* `max_line_length`
diff --git a/package.json b/package.json
@@ -22,6 +22,8 @@
     "cosmiconfig": "3.1.0",
     "dashify": "0.2.2",
     "diff": "3.2.0",
+    "editorconfig": "0.14.2",
+    "editorconfig-to-prettier": "0.0.1",
     "emoji-regex": "6.5.1",
     "escape-string-regexp": "1.0.5",
     "esutils": "2.0.2",
@@ -37,6 +39,7 @@
     "minimatch": "3.0.4",
     "minimist": "1.2.0",
     "parse5": "3.0.3",
+    "path-root": "0.1.1",
     "postcss-less": "1.1.1",
     "postcss-media-query-parser": "0.2.3",
     "postcss-scss": "1.0.2",

diff --git a/src/resolve-config-editorconfig.js b/src/resolve-config-editorconfig.js
@@ -0,0 +1,43 @@
+"use strict";
+
+const editorconfig = require("editorconfig");
+const mem = require("mem");
+const pathRoot = require("path-root");
+const editorConfigToPrettier = require("editorconfig-to-prettier");
+
+const maybeParse = (filePath, config, parse) => {
+  const root = filePath && pathRoot(filePath);
+  return filePath && !config && parse(filePath, { root });
+};
+
+const editorconfigAsyncNoCache = (filePath, config) => {
+  return Promise.resolve(maybeParse(filePath, config, editorconfig.parse)).then(
+    editorConfigToPrettier
+  );
+};
+const editorconfigAsyncWithCache = mem(editorconfigAsyncNoCache);
+
+const editorconfigSyncNoCache = (filePath, config) => {
+  return editorConfigToPrettier(
+    maybeParse(filePath, config, editorconfig.parseSync)
+  );
+};
+const editorconfigSyncWithCache = mem(editorconfigSyncNoCache);
+
+function getLoadFunction(opts) {
+  if (opts.sync) {
+    return opts.cache ? editorconfigSyncWithCache : editorconfigSyncNoCache;
+  }
+
+  return opts.cache ? editorconfigAsyncWithCache : editorconfigAsyncNoCache;
+}
+
+function clearCache() {
+  mem.clear(editorconfigSyncWithCache);
+  mem.clear(editorconfigAsyncWithCache);
+}
+
+module.exports = {
+  getLoadFunction,
+  clearCache
+};
diff --git a/src/resolve-config.js b/src/resolve-config.js
@@ -5,6 +5,8 @@ const minimatch = require("minimatch");
 const path = require("path");
 const mem = require("mem");
 
+const resolveEditorConfig = require("./resolve-config-editorconfig");
+
 const getExplorerMemoized = mem(opts =>
   cosmiconfig("prettier", {
     sync: opts.sync,
@@ -26,23 +28,43 @@ function getLoadFunction(opts) {
   return getExplorerMemoized(opts).load;
 }
 
-function resolveConfig(filePath, opts) {
+function _resolveConfig(filePath, opts, sync) {
   opts = Object.assign({ useCache: true }, opts);
-  const load = getLoadFunction({ cache: !!opts.useCache, sync: false });
-  return load(filePath, opts.config).then(result => {
-    return !result ? null : mergeOverrides(result, filePath);
-  });
+  const loadOpts = { cache: !!opts.useCache, sync: !!sync };
+  const load = getLoadFunction(loadOpts);
+  const loadEditorConfig = resolveEditorConfig.getLoadFunction(loadOpts);
+  const arr = [load, loadEditorConfig].map(l => l(filePath, opts.config));
+
+  const unwrapAndMerge = arr => {
+    const result = arr[0];
+    const editorConfigured = arr[1];
+    const merged = Object.assign(
+      {},
+      editorConfigured,
+      mergeOverrides(Object.assign({}, result), filePath)
+    );
+
+    if (Object.keys(merged).length === 0) {
+      return null;
+    }
+
+    return merged;
+  };
+
+  if (loadOpts.sync) {
+    return unwrapAndMerge(arr);
+  }
+
+  return Promise.all(arr).then(unwrapAndMerge);
 }
 
-resolveConfig.sync = (filePath, opts) => {
-  opts = Object.assign({ useCache: true }, opts);
-  const load = getLoadFunction({ cache: !!opts.useCache, sync: true });
-  const result = load(filePath, opts.config);
-  return !result ? null : mergeOverrides(result, filePath);
-};
+const resolveConfig = (filePath, opts) => _resolveConfig(filePath, opts, false);
+
+resolveConfig.sync = (filePath, opts) => _resolveConfig(filePath, opts, true);
 
 function clearCache() {
   mem.clear(getExplorerMemoized);
+  resolveEditorConfig.clearCache();
 }
 
 function resolveConfigFile(filePath) {

diff --git a/tests_integration/__tests__/__snapshots__/config-resolution.js.snap b/tests_integration/__tests__/__snapshots__/config-resolution.js.snap
@@ -3,7 +3,22 @@
 exports[`CLI overrides take precedence (stderr) 1`] = `""`;
 
 exports[`CLI overrides take precedence (stdout) 1`] = `
-"console.log(
+"function f() {
+	console.log(
+		\\"should have tab width 8\\"
+	)
+}
+function f() {
+  console.log(
+    \\"should have space width 2\\"
+  )
+}
+function f() {
+        console.log(
+                \\"should have space width 8\\"
+        )
+}
+console.log(
   \\"jest/__best-tests__/file.js should have semi\\"
 );
 console.log(
@@ -84,7 +99,16 @@ exports[`resolves configuration file with --find-config-path file (write) 1`] =
 exports[`resolves configuration from external files (stderr) 1`] = `""`;
 
 exports[`resolves configuration from external files (stdout) 1`] = `
-"console.log(\\"jest/__best-tests__/file.js should have semi\\");
+"function f() {
+	console.log(\\"should have tab width 8\\")
+}
+function f() {
+  console.log(\\"should have space width 2\\")
+}
+function f() {
+        console.log(\\"should have space width 8\\")
+}
+console.log(\\"jest/__best-tests__/file.js should have semi\\");
 console.log(\\"jest/Component.js should not have semi\\")
 console.log(\\"jest/Component.test.js should have semi\\");
 function js() {

diff --git a/tests_integration/__tests__/__snapshots__/with-config-precedence.js.snap b/tests_integration/__tests__/__snapshots__/with-config-precedence.js.snap
@@ -80,7 +80,22 @@ exports[`CLI overrides take lower precedence with --config-precedence file-overr
 exports[`CLI overrides take precedence with --config-precedence cli-override (stderr) 1`] = `""`;
 
 exports[`CLI overrides take precedence with --config-precedence cli-override (stdout) 1`] = `
-"console.log(
+"function f() {
+	console.log(
+		\\"should have tab width 8\\"
+	)
+}
+function f() {
+  console.log(
+    \\"should have space width 2\\"
+  )
+}
+function f() {
+        console.log(
+                \\"should have space width 8\\"
+        )
+}
+console.log(
   \\"jest/__best-tests__/file.js should have semi\\"
 );
 console.log(
@@ -137,7 +152,22 @@ exports[`CLI overrides take precedence with --config-precedence cli-override (wr
 exports[`CLI overrides take precedence without --config-precedence (stderr) 1`] = `""`;
 
 exports[`CLI overrides take precedence without --config-precedence (stdout) 1`] = `
-"console.log(
+"function f() {
+	console.log(
+		\\"should have tab width 8\\"
+	)
+}
+function f() {
+  console.log(
+    \\"should have space width 2\\"
+  )
+}
+function f() {
+        console.log(
+                \\"should have space width 8\\"
+        )
+}
+console.log(
   \\"jest/__best-tests__/file.js should have semi\\"
 );
 console.log(

diff --git a/tests_integration/__tests__/config-resolution.js b/tests_integration/__tests__/config-resolution.js
@@ -102,6 +102,98 @@ test("API resolveConfig.sync with file arg and extension override", () => {
   });
 });
 
+test("API resolveConfig with file arg and .editorconfig", () => {
+  const file = path.resolve(
+    path.join(__dirname, "../cli/config/editorconfig/file.js")
+  );
+  return prettier.resolveConfig(file).then(result => {
+    expect(result).toMatchObject({
+      useTabs: true,
+      tabWidth: 8,
+      printWidth: 100
+    });
+  });
+});
+
+test("API resolveConfig.sync with file arg and .editorconfig", () => {
+  const file = path.resolve(
+    path.join(__dirname, "../cli/config/editorconfig/file.js")
+  );
+  expect(prettier.resolveConfig.sync(file)).toMatchObject({
+    useTabs: true,
+    tabWidth: 8,
+    printWidth: 100
+  });
+});
+
+test("API resolveConfig with nested file arg and .editorconfig", () => {
+  const file = path.resolve(
+    path.join(__dirname, "../cli/config/editorconfig/lib/file.js")
+  );
+  return prettier.resolveConfig(file).then(result => {
+    expect(result).toMatchObject({
+      useTabs: false,
+      tabWidth: 2,
+      printWidth: 100
+    });
+  });
+});
+
+test("API resolveConfig.sync with nested file arg and .editorconfig", () => {
+  const file = path.resolve(
+    path.join(__dirname, "../cli/config/editorconfig/lib/file.js")
+  );
+  expect(prettier.resolveConfig.sync(file)).toMatchObject({
+    useTabs: false,
+    tabWidth: 2,
+    printWidth: 100
+  });
+});
+
+test("API resolveConfig with nested file arg and .editorconfig and indent_size = tab", () => {
+  const file = path.resolve(
+    path.join(__dirname, "../cli/config/editorconfig/lib/indent_size=tab.js")
+  );
+  return prettier.resolveConfig(file).then(result => {
+    expect(result).toMatchObject({
+      useTabs: false,
+      tabWidth: 8,
+      printWidth: 100
+    });
+  });
+});
+
+test("API resolveConfig.sync with nested file arg and .editorconfig and indent_size = tab", () => {
+  const file = path.resolve(
+    path.join(__dirname, "../cli/config/editorconfig/lib/indent_size=tab.js")
+  );
+  expect(prettier.resolveConfig.sync(file)).toMatchObject({
+    useTabs: false,
+    tabWidth: 8,
+    printWidth: 100
+  });
+});
+
+test("API resolveConfig with missing file arg", () => {
+  const file = path.resolve(
+    path.join(__dirname, "../cli/config/editorconfig/file.shouldnotexist")
+  );
+  return prettier.resolveConfig(file).then(result => {
+    expect(result).toBeNull();
+  });
+});
+
+test("API resolveConfig.sync with missing file arg", () => {
+  const file = path.resolve(
+    path.join(__dirname, "../cli/config/editorconfig/file.shouldnotexist")
+  );
+  expect(prettier.resolveConfig.sync(file)).toBeNull();
+});
+
+test("API clearConfigCache", () => {
+  expect(() => prettier.clearConfigCache()).not.toThrowError();
+});
+
 test("API resolveConfig.sync overrides work with absolute paths", () => {
   // Absolute path
   const file = path.join(__dirname, "../cli/config/filepath/subfolder/file.js");

diff --git a/tests_integration/cli/config/.prettierrc b/tests_integration/cli/config/.prettierrc
@@ -1,6 +1,7 @@
-semi: false
-
 overrides:
+- files: "*.js"
+  options:
+    semi: false
 - files: "*.ts"
   options:
     semi: true
diff --git a/tests_integration/cli/config/editorconfig/.editorconfig b/tests_integration/cli/config/editorconfig/.editorconfig
@@ -0,0 +1,15 @@
+root = true
+
+[*.js]
+indent_style = tab
+tab_width = 8
+indent_size = 2 # overridden by tab_width since indent_style = tab
+max_line_length = 100
+
+# Indentation override for all JS under lib directory
+[lib/**.js]
+indent_style = space
+indent_size = 2
+
+[lib/indent_size=tab.js]
+indent_size = tab
diff --git a/tests_integration/cli/config/editorconfig/file.js b/tests_integration/cli/config/editorconfig/file.js
@@ -0,0 +1,3 @@
+function f() {
+  console.log("should have tab width 8");
+}
diff --git a/tests_integration/cli/config/editorconfig/lib/file.js b/tests_integration/cli/config/editorconfig/lib/file.js
@@ -0,0 +1,3 @@
+function f() {
+  console.log("should have space width 2");
+}
diff --git a/tests_integration/cli/config/editorconfig/lib/indent_size=tab.js b/tests_integration/cli/config/editorconfig/lib/indent_size=tab.js
@@ -0,0 +1,3 @@
+function f() {
+  console.log("should have space width 8");
+}
diff --git a/tests_integration/cli/config/js/.editorconfig b/tests_integration/cli/config/js/.editorconfig
@@ -0,0 +1,4 @@
+# This file should be overridden by prettier.config.js
+
+[*]
+tab_width = 1
diff --git a/tests_integration/cli/config/package/.editorconfig b/tests_integration/cli/config/package/.editorconfig
@@ -0,0 +1,7 @@
+# This file should be overridden by package.json
+
+[*]
+tab_width = 1
+
+[*.ts]
+tab_width = 1