refs #964 Add a spec to check duplicate keys between translation and missing json

spec/config/i18n.spec.ts

@@ -24,4 +24,22 @@ describe('i18n', () => {
       })
     })
   })
+
+  describe('should not define duplicate keys', () => {
+    locales.map(locale => {
+      it(`${locale} translation`, () => {
+        const targetJson = JSON.parse(
+          fs.readFileSync(path.resolve(__dirname, `../../src/config/locales/${locale}/translation.json`), 'utf8')
+        )
+        const targetMissingJson = JSON.parse(
+          fs.readFileSync(path.resolve(__dirname, `../../src/config/locales/${locale}/translation.missing.json`), 'utf8')
+        )
+        const allKeys = keys(targetJson).concat(keys(targetMissingJson))
+        const duplicates: Array<string> = allKeys.filter(
+          (x: string, _: number, self: Array<string>) => self.indexOf(x) !== self.lastIndexOf(x)
+        )
+        expect(duplicates).toEqual([])
+      })
+    })
+  })
 })

src/config/locales/en/translation.missing.json

@@ -0,0 +1 @@
+{}

src/config/locales/ja/translation.missing.json

@@ -0,0 +1 @@
+{}