⭐ new: add pluralization (#44) by @mmochetti

src/extend.js

@@ -79,6 +79,14 @@ export default function (Vue) {
     return this.$options.locales[lang]
   }
 
+  function fetchChoice (locale, choice) {
+    if (!locale && typeof locale !== 'string') return null
+    const choices = locale.split('|')
+    choice = choice - 1
+    if (!choices[choice]) return locale
+    return choices[choice].trim()
+  }
+
   /**
    * Vue.t
    *
@@ -94,6 +102,19 @@ export default function (Vue) {
       || warnDefault(key)
   }
 
+  /**
+   * Vue.tc
+   *
+   * @param {String} key
+   * @param {number|undefined} choice
+   * @param {Array} ...args
+   * @return {String}
+   */
+
+  Vue.tc = (key, choice, ...args) => {
+    if (!choice) { choice = 1 }
+    return fetchChoice(Vue.t(key, ...args), choice)
+  }
 
   /**
    * $t
@@ -115,5 +136,20 @@ export default function (Vue) {
       || warnDefault(key)
   }
 
+  /**
+   * $tc
+   *
+   * @param {String} key
+   * @param {number|undefined} choice
+   * @param {Array} ...args
+   * @return {String}
+   */
+
+  Vue.prototype.$tc = function (key, choice, ...args) {
+    if (typeof choice !== 'number' && typeof choice !== 'undefined') return key
+    if (!choice) { choice = 1 }
+    return fetchChoice(this.$t(key, ...args), choice)
+  }
+
   return Vue
 }

test/specs/fixture/locales.js

@@ -12,7 +12,15 @@ export default {
     'hello world': 'Hello World',
     'Hello {0}': 'Hello {0}',
     'continue-with-new-account': 'continue with new account',
-    underscore: '{hello_msg} world'
+    underscore: '{hello_msg} world',
+    plurals: {
+      car: 'car | cars',
+      format: {
+        named: 'Hello {name}, how are you? | Hi {name}, you look fine',
+        list: 'Hello {0}, how are you? | Hi {0}, you look fine'
+      },
+      fallback: 'this is fallback | this is a plural fallback'
+    }
   },
   ja: {
     message: {
@@ -23,6 +31,14 @@ export default {
         list: 'こんにちは {0}, ごきげんいかが？'
       },
       fallback1: 'これはフォールバック'
+    },
+    plurals: {
+      car: 'ザ・ワールド | これはフォールバック',
+      format: {
+        named: 'こんにちは {name}, ごきげんいかが？ | こんにちは {name}, ごきげんいかが？',
+        list: 'こんにちは {0}, ごきげんいかが？| こんにちは {0}, ごきげんいかが？'
+      },
+      fallback: 'これはフォールバック | ザ・ワールド'
     }
   }
 }

test/specs/i18n.js

@@ -109,6 +109,106 @@ describe('i18n', () => {
     })
   })
 
+  describe('Vue.tc', () => {
+    describe('en language locale', () => {
+      it('should translate an english', () => {
+        assert.equal(Vue.tc('plurals.car', 1), 'car')
+      })
+    })
+
+    describe('multi plural check', () => {
+      it('should fetch pluralized string', () => {
+        assert.equal(Vue.tc('plurals.car', 2), 'cars')
+      })
+    })
+
+    describe('ja language locale', () => {
+      it('should translate a japanese', () => {
+        assert.equal(Vue.tc('plurals.car', 1, 'ja'), 'ザ・ワールド')
+      })
+    })
+
+    describe('key argument', () => {
+      describe('not specify', () => {
+        it('should return empty string', () => {
+          assert.equal(Vue.tc(), '')
+        })
+      })
+
+      describe('empty string', () => {
+        it('should return empty string', () => {
+          assert.equal(Vue.tc(''), '')
+        })
+      })
+
+      describe('not regist key', () => {
+        it('should return key string', () => {
+          assert.equal(Vue.tc('foo.bar'), 'foo.bar')
+        })
+      })
+
+      describe('sentence fragment', () => {
+        it('should translate fragment', () => {
+          assert.equal(Vue.tc('hello world'), 'Hello World')
+        })
+
+        it('should return replaced string if available', () => {
+          assert.equal(
+            Vue.tc('Hello {0}', 1, ['kazupon']),
+            'Hello kazupon'
+          )
+        })
+
+        it('should return key if unavailable', () => {
+          assert.equal(Vue.tc('Hello'), 'Hello')
+        })
+      })
+    })
+
+    describe('format arguments', () => {
+      context('named', () => {
+        it('should return replaced string', () => {
+          assert.equal(
+            Vue.tc('plurals.format.named', 1, { name: 'kazupon' }),
+            'Hello kazupon, how are you?'
+          )
+        })
+      })
+
+      context('list', () => {
+        it('should return replaced string', () => {
+          assert.equal(
+            Vue.tc('plurals.format.list', 1, ['kazupon']),
+            'Hello kazupon, how are you?'
+          )
+        })
+      })
+    })
+
+    describe('language argument', () => {
+      it('should return empty string', () => {
+        assert.equal(Vue.tc('plurals.car', 1, 'ja'), 'ザ・ワールド')
+      })
+    })
+
+    describe('format & language arguments', () => {
+      it('should return replaced string', () => {
+        assert.equal(
+          Vue.tc('plurals.format.list', 1, 'ja', ['kazupon']),
+          'こんにちは kazupon, ごきげんいかが？'
+        )
+      })
+    })
+
+    describe('fallback', () => {
+      it('should return fallback string', () => {
+        assert.equal(
+          Vue.tc('plurals.fallback', 1, 'ja'),
+          'これはフォールバック'
+        )
+      })
+    })
+  })
 
   describe('$t', () => {
     describe('en language locale', () => {
@@ -219,6 +319,115 @@ describe('i18n', () => {
   })
 
 
+  describe('$tc', () => {
+    describe('en language locale', () => {
+      it('should translate plural english', () => {
+        const vm = new Vue()
+        assert.equal(vm.$tc('plurals.car', 1), 'car')
+      })
+    })
+
+    describe('multi plural check', () => {
+      it('should fetch pluralized string', () => {
+        const vm = new Vue()
+        assert.equal(vm.$tc('plurals.car', 2), 'cars')
+      })
+    })
+
+    describe('key argument', () => {
+      describe('not specify', () => {
+        it('should return empty string', () => {
+          const vm = new Vue()
+          assert.equal(vm.$tc(), '')
+        })
+      })
+
+      describe('empty string', () => {
+        it('should return empty string', () => {
+          const vm = new Vue()
+          assert.equal(vm.$tc(''), '')
+        })
+      })
+
+      describe('not regist key', () => {
+        it('should return key string', () => {
+          const vm = new Vue()
+          assert.equal(vm.$tc('foo.bar'), 'foo.bar')
+        })
+      })
+
+      describe('sentence fragment', () => {
+        it('should translate fragment', () => {
+          const vm = new Vue()
+          assert.equal(vm.$tc('hello world'), 'Hello World')
+        })
+
+        it('should return replaced string if available', () => {
+          const vm = new Vue()
+          assert.equal(
+            vm.$tc('Hello {0}', 1, ['kazupon']),
+            'Hello kazupon'
+          )
+        })
+
+        it('should return key if unavailable', () => {
+          const vm = new Vue()
+          assert.equal(vm.$tc('Hello'), 'Hello')
+        })
+      })
+    })
+
+    describe('format arguments', () => {
+      context('named', () => {
+        it('should return replaced string', () => {
+          const vm = new Vue()
+          assert.equal(
+            vm.$tc('plurals.format.named', 1, { name: 'kazupon' }),
+            'Hello kazupon, how are you?'
+          )
+        })
+      })
+
+      context('list', () => {
+        it('should return replaced string', () => {
+          const vm = new Vue()
+          assert.equal(
+            vm.$tc('plurals.format.list', 1, ['kazupon']),
+            'Hello kazupon, how are you?'
+          )
+        })
+      })
+    })
+
+    describe('language argument', () => {
+      it('should return empty string', () => {
+        const vm = new Vue()
+        assert.equal(vm.$tc('plurals.car', 1, 'ja'), 'ザ・ワールド')
+      })
+    })
+
+    describe('format & language arguments', () => {
+      it('should return replaced string', () => {
+        const vm = new Vue()
+        assert.equal(
+          vm.$tc('plurals.format.list', 1, 'ja', ['kazupon']),
+          'こんにちは kazupon, ごきげんいかが？'
+        )
+      })
+    })
+
+    describe('fallback', () => {
+      it('should return fallback string', () => {
+        const vm = new Vue()
+        assert.equal(
+          vm.$tc('plurals.fallback', 2, 'ja'),
+          'ザ・ワールド'
+        )
+      })
+    })
+  })
+
+
   describe('reactive translation', () => {
     let el
     beforeEach(() => {