fix(web): FormatMessage development keys (#10536)

web/src/lib/components/i18n/__test__/format-message.spec.ts

@@ -2,13 +2,10 @@ import FormatTagB from '$lib/components/i18n/__test__/format-tag-b.svelte';
 import FormatMessage from '$lib/components/i18n/format-message.svelte';
 import '@testing-library/jest-dom';
 import { render, screen } from '@testing-library/svelte';
-import { init, json, locale, register, waitLocale } from 'svelte-i18n';
-import { get } from 'svelte/store';
+import { init, locale, register, waitLocale } from 'svelte-i18n';
 import { describe } from 'vitest';
 
 describe('FormatMessage component', () => {
-  let $json: (id: string, locale?: string | undefined) => unknown;
-
   beforeAll(async () => {
     register('en', () =>
       Promise.resolve({
@@ -21,12 +18,11 @@ describe('FormatMessage component', () => {
 
     await init({ fallbackLocale: 'en' });
     await waitLocale('en');
-    $json = get(json);
   });
 
   it('formats a plain text message', () => {
     render(FormatMessage, {
-      message: $json('hello'),
+      key: 'hello',
       values: { name: 'test' },
     });
     expect(screen.getByText('Hello test')).toBeInTheDocument();
@@ -34,20 +30,20 @@ describe('FormatMessage component', () => {
 
   it('throws an error when locale is empty', async () => {
     await locale.set(undefined);
-    expect(() => render(FormatMessage, { message: undefined })).toThrowError();
+    expect(() => render(FormatMessage, { key: '' })).toThrowError();
     await locale.set('en');
   });
 
   it('shows raw message when value is empty', () => {
     render(FormatMessage, {
-      message: $json('hello'),
+      key: 'hello',
     });
     expect(screen.getByText('Hello {name}')).toBeInTheDocument();
   });
 
   it('shows message when slot is empty', () => {
     render(FormatMessage, {
-      message: $json('html'),
+      key: 'html',
       values: { name: 'test' },
     });
     expect(screen.getByText('Hello test')).toBeInTheDocument();
@@ -55,7 +51,7 @@ describe('FormatMessage component', () => {
 
   it('renders a message with html', () => {
     const { container } = render(FormatTagB, {
-      message: $json('html'),
+      key: 'html',
       values: { name: 'test' },
     });
     expect(container.innerHTML).toBe('Hello <strong>test</strong>');
@@ -63,7 +59,7 @@ describe('FormatMessage component', () => {
 
   it('renders a message with html and plural', () => {
     const { container } = render(FormatTagB, {
-      message: $json('plural'),
+      key: 'plural',
       values: { count: 1 },
     });
     expect(container.innerHTML).toBe('You have <strong>1 item</strong>');
@@ -71,8 +67,13 @@ describe('FormatMessage component', () => {
 
   it('protects agains XSS injection', () => {
     render(FormatMessage, {
-      message: $json('xss'),
+      key: 'xss',
     });
     expect(screen.getByText('<image/src/onerror=prompt(8)>')).toBeInTheDocument();
   });
+
+  it('displays the message key when not found', () => {
+    render(FormatMessage, { key: 'invalid.key' });
+    expect(screen.getByText('invalid.key')).toBeInTheDocument();
+  });
 });

web/src/lib/components/i18n/__test__/format-tag-b.svelte

@@ -2,11 +2,11 @@
   import FormatMessage from '../format-message.svelte';
   import type { ComponentProps } from 'svelte';
 
-  export let message: unknown;
+  export let key: string;
   export let values: ComponentProps<FormatMessage>['values'];
 </script>
 
-<FormatMessage {message} {values} let:tag let:message>
+<FormatMessage {key} {values} let:tag let:message>
   {#if tag === 'b'}
     <strong>{message}</strong>
   {/if}

web/src/lib/components/i18n/format-message.svelte

@@ -1,11 +1,11 @@
 <script lang="ts">
   import { IntlMessageFormat, type FormatXMLElementFn, type PrimitiveType } from 'intl-messageformat';
   import { TYPE, type MessageFormatElement } from '@formatjs/icu-messageformat-parser';
-  import { locale as i18nLocale } from 'svelte-i18n';
+  import { locale as i18nLocale, json } from 'svelte-i18n';
 
   type InterpolationValues = Record<string, PrimitiveType | FormatXMLElementFn<unknown>>;
 
-  export let message: unknown;
+  export let key: string;
   export let values: InterpolationValues = {};
 
   const getLocale = (locale?: string | null) => {
@@ -16,13 +16,13 @@
     return locale;
   };
 
-  const getElements = (message: unknown, locale: string): MessageFormatElement[] => {
+  const getElements = (message: string, locale: string): MessageFormatElement[] => {
     return new IntlMessageFormat(message as string, locale, undefined, {
       ignoreTag: false,
     }).getAst();
   };
 
-  const getParts = (message: unknown, locale: string) => {
+  const getParts = (message: string, locale: string) => {
     try {
       const elements = getElements(message, locale);
 
@@ -38,12 +38,13 @@
       });
     } catch (error) {
       if (error instanceof Error) {
-        console.warn(`Message "${message}" has syntax error:`, error.message);
+        console.warn(`Message "${key}" has syntax error:`, error.message);
       }
       return [{ message: message as string, tag: undefined }];
     }
   };
 
+  $: message = ($json(key) as string) || key;
   $: locale = getLocale($i18nLocale);
   $: parts = getParts(message, locale);
 </script>