feat: support localePattern option for locale structured with directory

docs/started.md

@@ -44,17 +44,25 @@ module.export = {
       // or
       // localeDir: {
       //   pattern: './path/to/locales/*.{json,json5,yaml,yml}', // extension is glob formatting!
-      //   localeKey: 'file' // or 'key'
+      //   localeKey: 'file' // or 'path' or 'key'
       // }
       // or
       // localeDir: [
       //   {
+      //     // 'file' case
       //     pattern: './path/to/locales1/*.{json,json5,yaml,yml}',
-      //     localeKey: 'file' // or 'key'
+      //     localeKey: 'file'
       //   },
       //   {
+      //     // 'path' case
       //     pattern: './path/to/locales2/*.{json,json5,yaml,yml}',
-      //     localeKey: 'file' // or 'key'
+      //     localePattern: /^.*\/(?<locale>[A-Za-z0-9-_]+)\/.*\.(json5?|ya?ml)$/,
+      //     localeKey: 'path'
+      //   },
+      //   {
+      //     // 'key' case
+      //     pattern: './path/to/locales3/*.{json,json5,yaml,yml}',
+      //     localeKey: 'key'
       //   },
       // ]
 
@@ -71,15 +79,25 @@ See [the rule list](../rules/)
 ### `settings['vue-i18n']`
 
 - `localeDir` ... You can specify a string or an object or an array.
+
   - String option ... A glob for specifying files that store localization messages of project.
   - Object option
     - `pattern` (`string`) ... A glob for specifying files that store localization messages of project.
-    - `localeKey` (`'file' | 'key'`) ... Specifies how to determine the locale for localization messages.
+    - `localeKey` (`'file' | 'path' | 'key'`) ... Specifies how to determine the locale for localization messages.
       - `'file'` ... Determine the locale name from the filename. The resource file should only contain messages for that locale. Use this option if you use `vue-cli-plugin-i18n`. This option is also used when String option is specified.
+      - `'path'` ... Determine the locale name from the path. In this case, the locale must be had structured with your rule on the path. It can be captured with the regular expression named capture. The resource file should only contain messages for that locale.
       - `'key'` ... Determine the locale name from the root key name of the file contents. The value of that key should only contain messages for that locale. Used when the resource file is in the format given to the `messages` option of the `VueI18n` constructor option.
-  - Array option ... An array of String option and Object option. Useful if you have multiple locale directories.
+  - `localePattern` ... Specifies how to determine pattern the locale for localization messages. This option means, when `localeKey` is `'path'`, you will need to capture the locale using a regular expression. You need to use the locale capture as a named capture `?<locale>`, so it’s be able to capture from the path of the locale resources. If you omit it, it will be captured from the resource path with the same regular expression pattern as `vue-cli-plugin-i18n`.
+
+- Array option ... An array of String option and Object option. Useful if you have multiple locale directories.
 - `messageSyntaxVersion` (Optional) ... Specify the version of `vue-i18n` you are using. If not specified, the message will be parsed twice. Also, some rules require this setting.
 
+::: warn NOTE
+
+The `localePattern` options does not support SFC i18n custom blocks (`src` attribute), only for resources of files to import when specified in VueI18n's `messages` options (VueI18n v9 and later, `messages` specified in `createI18n`) for resources of files to import.
+
+:::
+
 ### Running ESLint from command line
 
 If you want to run `eslint` from command line, make sure you include the `.vue`, `.json`, `.json5`, `.yaml` and `.yml` extension using [the `--ext` option](https://eslint.org/docs/user-guide/configuring#specifying-file-extensions-to-lint) or a glob pattern because ESLint targets only `.js` files by default.

lib/rules/key-format-style.ts

@@ -63,7 +63,7 @@ function create(context: RuleContext): RuleListener {
       upper?: KeyStack
     }
     let keyStack: KeyStack = {
-      inLocale: targetLocaleMessage.localeKey === 'file'
+      inLocale: targetLocaleMessage.isResolvedLocaleByFileName()
     }
     return {
       JSONProperty(node: JSONAST.JSONProperty) {
@@ -110,7 +110,7 @@ function create(context: RuleContext): RuleListener {
       upper?: KeyStack
     }
     let keyStack: KeyStack = {
-      inLocale: targetLocaleMessage.localeKey === 'file'
+      inLocale: targetLocaleMessage.isResolvedLocaleByFileName()
     }
     function withinKey(node: YAMLAST.YAMLNode) {
       for (const keyNode of yamlKeyNodes) {

lib/rules/no-duplicate-keys-in-locale.ts

@@ -47,7 +47,7 @@ function create(context: RuleContext): RuleListener {
     targetLocaleMessage: LocaleMessage,
     otherLocaleMessages: LocaleMessage[]
   ): PathStack {
-    if (targetLocaleMessage.localeKey === 'file') {
+    if (targetLocaleMessage.isResolvedLocaleByFileName()) {
       const locale = targetLocaleMessage.locales[0]
       return createInitLocalePathStack(locale, otherLocaleMessages)
     } else {

lib/rules/no-missing-keys-in-other-locales.ts

@@ -115,7 +115,7 @@ function create(context: RuleContext): RuleListener {
           }[]
         }
     let keyStack: KeyStack
-    if (targetLocaleMessage.localeKey === 'file') {
+    if (targetLocaleMessage.isResolvedLocaleByFileName()) {
       const locale = targetLocaleMessage.locales[0]
       keyStack = {
         locale,

lib/types/settings.ts

@@ -2,10 +2,12 @@
  * How to determine the locale for localization messages.
  * - `'file'` ... Determine the locale name from the filename. The resource file should only contain messages for that locale.
  *                Use this option if you use `vue-cli-plugin-i18n`. This method is also used when String option is specified.
- * - `'key'` ...  Determine the locale name from the root key name of the file contents. The value of that key should only contain messages for that locale.
+ * - `'path'` ... Determine the locale name from the path of resource. In this case, the locale must be had structured with your rule on the path.
+ *                It can be captured with the regular expression named capture. The resource file should only contain messages for that locale.
+ * - `'key'`  ... Determine the locale name from the root key name of the file contents. The value of that key should only contain messages for that locale.
  *                Used when the resource file is in the format given to the `messages` option of the `VueI18n` constructor option.
  */
-export type LocaleKeyType = 'file' | 'key'
+export type LocaleKeyType = 'file' | 'path' | 'key'
 /**
  * Type of `settings['vue-i18n'].localeDir`
  */
@@ -29,4 +31,12 @@ export interface SettingsVueI18nLocaleDirObject {
    * Specifies how to determine the locale for localization messages.
    */
   localeKey: LocaleKeyType
+  /**
+   * Specifies how to determine pattern the locale for localization messages.
+   *
+   * This option means, when `localeKey` is `'path'`, you will need to capture the locale using a regular expression.
+   * You need to use the locale capture as a named capture `?<locale>`, so it’s be able to capture from the path of the locale resources.
+   * If you omit it, it will be captured from the resource path with the same regular expression pattern as `vue-cli-plugin-i18n`.
+   */
+  localePattern?: string | RegExp
 }

lib/utils/casing.ts

@@ -111,7 +111,7 @@ const checkersMap = {
 /**
  * Convert text to camelCase
  */
-export function camelCase(str: string) {
+export function camelCase(str: string): string {
   if (isPascalCase(str)) {
     return str.charAt(0).toLowerCase() + str.slice(1)
   }

lib/utils/index.ts

@@ -29,6 +29,7 @@ import { getCwd } from './get-cwd'
 interface LocaleFiles {
   files: string[]
   localeKey: LocaleKeyType
+  localePattern?: string | RegExp
 }
 const UNEXPECTED_ERROR_LOCATION = { line: 1, column: 0 }
 /**
@@ -112,15 +113,17 @@ function loadLocaleMessages(
 ): FileLocaleMessage[] {
   const results: FileLocaleMessage[] = []
   const checkDupeMap: { [file: string]: LocaleKeyType[] } = {}
-  for (const { files, localeKey } of localeFilesList) {
+  for (const { files, localeKey, localePattern } of localeFilesList) {
     for (const file of files) {
       const localeKeys = checkDupeMap[file] || (checkDupeMap[file] = [])
       if (localeKeys.includes(localeKey)) {
         continue
       }
       localeKeys.push(localeKey)
       const fullpath = resolve(cwd, file)
-      results.push(new FileLocaleMessage({ fullpath, localeKey }))
+      results.push(
+        new FileLocaleMessage({ fullpath, localeKey, localePattern })
+      )
     }
   }
   return results
@@ -225,7 +228,8 @@ class LocaleDirLocaleMessagesCache {
     } else {
       return {
         files: targetFilesLoader.get(localeDir.pattern, cwd),
-        localeKey: String(localeDir.localeKey ?? 'file') as LocaleKeyType
+        localeKey: String(localeDir.localeKey ?? 'file') as LocaleKeyType,
+        localePattern: localeDir.localePattern
       }
     }
   }

lib/utils/locale-messages.ts

@@ -20,34 +20,50 @@ import JSON5 from 'json5'
 import yaml from 'js-yaml'
 import { joinPath, parsePath } from './key-path'
 
+// see https://github.com/kazupon/vue-cli-plugin-i18n/blob/e9519235a454db52fdafcd0517ce6607821ef0b4/generator/templates/js/src/i18n.js#L10
+const DEFAULT_LOCALE_PATTERN = '[A-Za-z0-9-_]+'
+const DEFAULT_LOCALE_FIELNAME_REGEX = new RegExp(
+  `(${DEFAULT_LOCALE_PATTERN})\.`,
+  'i'
+)
+const DEFAULT_LOCALE_CAPTURE_REGEX = new RegExp(
+  `^.*\/(?<locale>${DEFAULT_LOCALE_PATTERN})\.(json5?|ya?ml)$`,
+  'i'
+)
+
 /**
  * The localization message class
  */
 export abstract class LocaleMessage {
   public readonly fullpath: string
   public readonly localeKey: LocaleKeyType
   public readonly file: string
+  public readonly localePattern: RegExp
   private _locales: string[] | undefined
   /**
    * @param {object} arg
    * @param {string} arg.fullpath Absolute path.
    * @param {string[]} [arg.locales] The locales.
    * @param {LocaleKeyType} arg.localeKey Specifies how to determine the locale for localization messages.
+   * @param {RegExp} args.localePattern Specifies how to determin the regular expression pattern for how to get the locale.
    */
   constructor({
     fullpath,
     locales,
-    localeKey
+    localeKey,
+    localePattern
   }: {
     fullpath: string
     locales?: string[]
     localeKey: LocaleKeyType
+    localePattern?: string | RegExp
   }) {
     this.fullpath = fullpath
     /** @type {LocaleKeyType} Specifies how to determine the locale for localization messages. */
     this.localeKey = localeKey
     /** @type {string} The localization messages file name. */
     this.file = fullpath.replace(/^.*(\\|\/|:)/, '')
+    this.localePattern = this.getLocalePatternWithRegex(localePattern)
 
     this._locales = locales
   }
@@ -57,6 +73,20 @@ export abstract class LocaleMessage {
    */
   abstract getMessagesInternal(): I18nLocaleMessageDictionary
 
+  /**
+   * Get locale pattern with regular expression
+   */
+  getLocalePatternWithRegex(localePattern?: string | RegExp): RegExp {
+    // prettier-ignore
+    return localePattern != null
+      ? typeof localePattern === 'string'
+        ? new RegExp(localePattern, 'i')
+        : Object.prototype.toString.call(localePattern) === '[object RegExp]'
+          ? localePattern
+          : DEFAULT_LOCALE_CAPTURE_REGEX
+      : DEFAULT_LOCALE_CAPTURE_REGEX
+  }
+
   /**
    * @returns {object} The localization messages object.
    */
@@ -71,20 +101,28 @@ export abstract class LocaleMessage {
       return this._locales
     }
     if (this.localeKey === 'file') {
-      // see https://github.com/kazupon/vue-cli-plugin-i18n/blob/e9519235a454db52fdafcd0517ce6607821ef0b4/generator/templates/js/src/i18n.js#L10
-      const matched = this.file.match(/([A-Za-z0-9-_]+)\./i)
+      const matched = this.file.match(DEFAULT_LOCALE_FIELNAME_REGEX)
       return (this._locales = [(matched && matched[1]) || this.file])
+    } else if (this.localeKey === 'path') {
+      const matched = this.fullpath.match(this.localePattern)
+      return (this._locales = [
+        (matched && matched.groups?.locale) || this.fullpath
+      ])
     } else if (this.localeKey === 'key') {
       return (this._locales = Object.keys(this.messages))
     }
     return (this._locales = [])
   }
 
+  isResolvedLocaleByFileName() {
+    return this.localeKey === 'file' || this.localeKey === 'path'
+  }
+
   /**
    * Gets messages for the given locale.
    */
   getMessagesFromLocale(locale: string): I18nLocaleMessageDictionary {
-    if (this.localeKey === 'file') {
+    if (this.isResolvedLocaleByFileName()) {
       if (!this.locales.includes(locale)) {
         return {}
       }
@@ -158,20 +196,24 @@ export class FileLocaleMessage extends LocaleMessage {
    * @param {string} arg.fullpath Absolute path.
    * @param {string[]} [arg.locales] The locales.
    * @param {LocaleKeyType} arg.localeKey Specifies how to determine the locale for localization messages.
+   * @param {string | RegExp} args.localePattern Specifies how to determin the regular expression pattern for how to get the locale.
    */
   constructor({
     fullpath,
     locales,
-    localeKey
+    localeKey,
+    localePattern
   }: {
     fullpath: string
     locales?: string[]
     localeKey: LocaleKeyType
+    localePattern?: string | RegExp
   }) {
     super({
       fullpath,
       locales,
-      localeKey
+      localeKey,
+      localePattern
     })
     this._resource = new ResourceLoader(fullpath, fileName => {
       const ext = extname(fileName).toLowerCase()

tests/fixtures/no-unused-keys/valid/path-locales/locales/en/message.json

@@ -0,0 +1,10 @@
+{
+  "hello": "hello world",
+  "messages": {
+    "hello": "hi DIO!",
+    "link": "@:messages.hello"
+  },
+  "hello_dio": "hello underscore DIO!",
+  "hello {name}": "hello {name}!",
+  "term": "I accept xxx {0}."
+}

tests/fixtures/no-unused-keys/valid/path-locales/locales/ja/message.yaml

@@ -0,0 +1,7 @@
+hello: "ハローワールド"
+messages:
+  hello: "こんにちは、DIO！"
+  link: "@:messages.hello"
+hello_dio: "こんにちは、アンダースコア DIO！"
+"hello {name}": "こんにちは、{name}！"
+term: "私は xxx の{0}に同意します。"

tests/fixtures/no-unused-keys/valid/path-locales/src/App.vue

@@ -0,0 +1,17 @@
+<template>
+  <div id="app">
+    <p v-t="'hello_dio'">{{ $t('messages.link') }}</p>
+    <i18n path="term" tag="label" for="tos">
+      <a :href="url" target="_blank">{{ $t('tos') }}</a>
+    </i18n>
+  </div>
+</template>
+
+<script>
+export default {
+  name: 'App',
+  created() {
+    this.$i18n.t('hello {name}', { name: 'DIO' })
+  }
+}
+</script>

tests/fixtures/no-unused-keys/valid/path-locales/src/main.js

@@ -0,0 +1,2 @@
+const $t = () => {}
+$t('hello')

tests/fixtures/utils/locale-messages/locales/en.yaml

@@ -0,0 +1 @@
+hello: world

tests/fixtures/utils/locale-messages/locales/en/message.json

@@ -0,0 +1,3 @@
+{
+  "hello": "world"
+}

tests/fixtures/utils/locale-messages/locales/message.json5

@@ -0,0 +1,8 @@
+{
+  en: {
+    hello: "world"
+  },
+  ja: {
+    hello: "ワールド"
+  }
+}

tests/lib/rules/no-unused-keys.ts

@@ -146,6 +146,19 @@ new RuleTester({
                 src: '.'
               }
             ]
+          }),
+          ...getTestCasesFromFixtures({
+            cwd: join(cwdRoot, './valid/path-locales'),
+            localeDir: {
+              pattern: `./locales/**/*.{json,yaml,yml}`,
+              localeKey: 'path',
+              localePattern: /^.*\/(?<locale>[A-Za-z0-9-_]+)\/.*\.(json5?|ya?ml)$/
+            },
+            options: [
+              {
+                src: '.'
+              }
+            ]
           })
         ]
       : []),
@@ -1021,6 +1034,10 @@ ${' '.repeat(6)}
         'constructor-option-format/src/main.js': true,
         'multiple-locales/src/App.vue': true,
         'multiple-locales/src/main.js': true,
+        'path-locales/locales/en/message.json': true,
+        'path-locales/locales/ja/message.yaml': true,
+        'path-locales/src/App.vue': true,
+        'path-locales/src/main.js': true,
         'vue-cli-format/src/App.vue': true,
         'vue-cli-format/src/main.js': true,
         'constructor-option-format/locales/index.json': {