fix(core-base): fallback interpolation should not break in runtime only (fix #768) (#784)

* fix(core-base): fallback interpolation should not break in runtime only

* style: lint

Author: AlexandreBonaventure

packages/core-base/src/translate.ts

@@ -342,6 +342,7 @@ export function translate<
     fallbackFormat,
     postTranslation,
     unresolving,
+    messageCompiler,
     fallbackLocale,
     messages
   } = context
@@ -368,7 +369,7 @@ export function translate<
         ? options.default
         : key
       : fallbackFormat // default by `fallbackFormat` option
-        ? key
+        ? (!messageCompiler ? () => key : key)
         : ''
   const enableDefaultMsg = fallbackFormat || defaultMsgOrKey !== ''
   const locale = isString(options.locale) ? options.locale : context.locale

packages/core-base/test/translate.test.ts

@@ -500,6 +500,28 @@ describe('context fallbackFormat option', () => {
       `Not found 'hi, {name}!' key in 'en' locale messages.`
     )
   })
+
+  test('runtimeOnly', () => {
+    const mockWarn = warn as jest.MockedFunction<typeof warn>
+    mockWarn.mockImplementation(() => {})
+
+    const ctx = context({
+      locale: 'en',
+      fallbackFormat: true,
+      messages: {
+        en: {}
+      }
+    })
+    ctx.messageCompiler = null
+
+    expect(translate(ctx, 'hi, {name}!', { name: 'kazupon' })).toEqual(
+      'hi, {name}!'
+    )
+    expect(mockWarn).toHaveBeenCalledTimes(1)
+    expect(mockWarn.mock.calls[0][0]).toEqual(
+      `Not found 'hi, {name}!' key in 'en' locale messages.`
+    )
+  })
 })
 
 describe('context unresolving option', () => {