Handle toString; add tests for other builtins

This changes current support for __proto__ in key paths.

See: kazupon#1706

src/index.js

@@ -165,8 +165,7 @@ export default class VueI18n {
       if (!message || !key) { return false }
       if (!isNull(this._path.getPathValue(message, key))) { return true }
       // fallback for flat key
-      if (message[key]) { return true }
-      return false
+      return Object.prototype.hasOwnProperty.call(message, key)
     }
 
     if (this._warnHtmlInMessage === 'warn' || this._warnHtmlInMessage === 'error') {

src/path.js

@@ -288,6 +288,9 @@ export default class I18nPath {
       let last: any = obj
       let i: number = 0
       while (i < length) {
+        if (!Object.prototype.hasOwnProperty.call(last, paths[i])) {
+          return null
+        }
         const value: any = last[paths[i]]
         if (value === undefined || value === null) {
           return null

test/unit/basic.test.js

@@ -660,6 +660,89 @@ describe('basic', () => {
         assert(vm.$te('message.hello', 'xx') === false)
       })
     })
+
+    describe('builtin property handling', () => {
+      [
+        // '__proto__', // TODO: see https://github.com/kazupon/vue-i18n/issues/1706
+        'constructor',
+        'hasOwnProperty',
+        'isPrototypeOf',
+        'propertyIsEnumerable',
+        'toLocaleString',
+        'toString',
+        'valueOf'
+      ].forEach(k => {
+        describe('top-level props', () => {
+          describe('existing key', () => {
+            let vm;
+            beforeEach(() => {
+              const i18n = new VueI18n({
+                locale: 'en',
+                fallbackLocale: 'en',
+                messages: {
+                  en: {
+                    [k]: 'i exist'
+                  },
+                  ja: {
+                    [k]: 'i exist (ja)'
+                  },
+                },
+                modifiers: {
+                  custom: str => str.replace(/[aeiou]/g, 'x')
+                }
+              })
+              vm = new Vue({ i18n })
+            })
+
+            it('should return true', () => {
+              assert(vm.$te(k) === true)
+            })
+
+            it('should return true with locale', () => {
+              assert(vm.$te(k, 'ja') === true)
+            })
+          })
+
+          describe('not existing key', () => {
+            it('should return false', () => {
+              const vm = new Vue({ i18n })
+              assert(vm.$te(k) === false)
+            })
+
+            it('should return false with locale', () => {
+              const vm = new Vue({ i18n })
+              assert(vm.$te(k, 'ja') === false)
+            })
+          })
+        })
+
+        describe('deep props', () => {
+          describe('existing key', () => {
+            it('should return true', () => {
+              const vm = new Vue({ i18n })
+              assert(vm.$te(`issues.builtins.existing.${k}`) === true)
+            })
+
+            it('should return true with locale', () => {
+              const vm = new Vue({ i18n })
+              assert(vm.$te(`issues.builtins.existing.${k}`, 'ja') === true)
+            })
+          })
+
+          describe('not existing key', () => {
+            it('should return false', () => {
+              const vm = new Vue({ i18n })
+              assert(vm.$te(`issues.builtins.missing.${k}`) === false)
+            })
+
+            it('should return false with locale', () => {
+              const vm = new Vue({ i18n })
+              assert(vm.$te(`issues.builtins.missing.${k}`, 'ja') === false)
+            })
+          })
+        })
+      })
+    })
   })
 
   describe('i18n#locale', () => {

test/unit/fixture/index.js

@@ -1,4 +1,4 @@
-export default {
+module.exports = {
   en: {
     message: {
       hello: 'the world',
@@ -70,7 +70,20 @@ export default {
       ]
     ],
     issues: {
-      arrayBugs: ['bug1', 'bug2']
+      arrayBugs: ['bug1', 'bug2'],
+      builtins: {
+        existing: {
+          // '__proto__': 'i exist', // TODO
+          'constructor': 'i exist',
+          'hasOwnProperty': 'i exist',
+          'isPrototypeOf': 'i exist',
+          'propertyIsEnumerable': 'i exist',
+          'toLocaleString': 'i exist',
+          'toString': 'i exist',
+          'valueOf': 'i exist'
+        },
+        missing: {}
+      }
     },
     'foo.bar.buz': 'hello flat key!'
   },
@@ -111,7 +124,20 @@ export default {
       ]
     ],
     issues: {
-      arrayBugs: ['バグ1', 'バグ2']
+      arrayBugs: ['バグ1', 'バグ2'],
+      builtins: {
+        existing: {
+          // '__proto__': 'i exist (ja)', // TODO
+          'constructor': 'i exist (ja)',
+          'hasOwnProperty': 'i exist (ja)',
+          'isPrototypeOf': 'i exist (ja)',
+          'propertyIsEnumerable': 'i exist (ja)',
+          'toLocaleString': 'i exist (ja)',
+          'toString': 'i exist (ja)',
+          'valueOf': 'i exist (ja)'
+        },
+        missing: {}
+      }
     },
     'foo.bar.buz': 'こんにちは、フラットなキーさん！'
   }