Fixes #469: Adds support for fastify handlebars view engine

docs/guides/view_engines/handlebars.md

@@ -20,6 +20,20 @@ To enable [**handlebars**](https://handlebarsjs.com) support make use of the `vi
 
 Handlebars is imported dynamically, so make sure to install it (`npm i hbs`). Otherwise `nestjs-i18n` can't register the helper function.
 
+## Fastify
+
+To use handlebars with fastify, `handlebars` is used instead of `hbs`. Make sure to install it (`npm i handlebars`).
+
+```diff title="src/app.module.ts"
+  I18nModule.forRoot({
+    fallbackLanguage: 'en',
+    loaderOptions: {
+      path: path.join(__dirname, '/i18n/'),
+    },
++   viewEngine: 'handlebars'
+  })
+```
+
 :::
 
 ## Example usage

package.json

@@ -96,6 +96,7 @@
     "eslint-plugin-prettier": "^5.0.0",
     "graphql-subscriptions": "^2.0.0",
     "graphql-tag": "^2.12.6",
+    "handlebars": "^4.7.8",
     "hbs": "^4.2.0",
     "jest": "^29.7.0",
     "pug": "^3.0.2",

src/i18n.module.ts

@@ -75,13 +75,21 @@ export class I18nModule implements OnModuleInit, OnModuleDestroy, NestModule {
     await this.i18n.refresh();
 
     // Register handlebars helper
-    if (this.i18nOptions.viewEngine == 'hbs') {
+    if (
+      this.i18nOptions.viewEngine == 'hbs' ||
+      this.i18nOptions.viewEngine == 'handlebars'
+    ) {
       try {
-        const hbs = await import('hbs');
+        // Import handlebars or hbs
+        const hbs =
+          this.i18nOptions.viewEngine === 'hbs'
+            ? await import('hbs')
+            : await import('handlebars');
+
         hbs.registerHelper('t', this.i18n.hbsHelper);
         logger.log('Handlebars helper registered');
       } catch (e) {
-        logger.error('hbs module failed to load', e);
+        logger.error(this.i18nOptions.viewEngine + ' module failed to load', e);
       }
     }
 

src/interfaces/i18n-options.interface.ts

@@ -48,7 +48,7 @@ export interface I18nOptions {
   loaderOptions: any;
   formatter?: Formatter;
   logging?: boolean;
-  viewEngine?: 'hbs' | 'pug' | 'ejs';
+  viewEngine?: 'hbs' | 'handlebars' | 'pug' | 'ejs';
   disableMiddleware?: boolean;
   skipAsyncHook?: boolean;
   validatorOptions?: I18nValidatorOptions;

tests/i18n-handlebars.e2e.spec.ts

@@ -0,0 +1,103 @@
+import { Test } from '@nestjs/testing';
+import * as path from 'path';
+import {
+  CookieResolver,
+  HeaderResolver,
+  AcceptLanguageResolver,
+  I18nModule,
+  QueryResolver,
+  I18nJsonLoader,
+} from '../src';
+import * as request from 'supertest';
+import { HelloController } from './app/controllers/hello.controller';
+import { NestFastifyApplication } from '@nestjs/platform-fastify';
+import { join } from 'path';
+import { Global, Module } from '@nestjs/common';
+
+@Global()
+@Module({
+  providers: [
+    {
+      provide: 'OPTIONS',
+      useValue: ['lang', 'locale', 'l'],
+    },
+  ],
+  exports: ['OPTIONS'],
+})
+export class OptionsModule {}
+
+describe('i18n module e2e handlebars', () => {
+  let app: NestFastifyApplication;
+
+  beforeAll(async () => {
+    const module = await Test.createTestingModule({
+      imports: [
+        OptionsModule,
+        I18nModule.forRoot({
+          fallbackLanguage: 'en',
+          fallbacks: {
+            'en-CA': 'fr',
+            'en-*': 'en',
+            'fr-*': 'fr',
+            fr: 'fr-FR',
+            pt: 'pt-BR',
+          },
+          resolvers: [
+            {
+              use: QueryResolver,
+              useFactory: (options) => {
+                return options;
+              },
+              inject: ['OPTIONS'],
+            },
+            new HeaderResolver(['x-custom-lang']),
+            new CookieResolver(),
+            AcceptLanguageResolver,
+          ],
+          loaderOptions: {
+            path: path.join(__dirname, '/i18n/'),
+          },
+          viewEngine: 'handlebars',
+        }),
+      ],
+      controllers: [HelloController],
+    }).compile();
+
+    app = module.createNestApplication<NestFastifyApplication>();
+
+    app.setViewEngine({
+      engine: {
+        handlebars: require('handlebars'),
+      },
+      templates: join(__dirname, 'app', 'views/hbs'),
+    });
+
+    await app.init();
+  });
+
+  it(`should render translated page`, async () => {
+    await request(app.getHttpServer())
+      .get('/hello/index')
+      .expect(200)
+      .expect('Every day');
+
+    await request(app.getHttpServer())
+      .get('/hello/index?l=nl')
+      .expect(200)
+      .expect('Iedere dag');
+
+    await request(app.getHttpServer())
+      .get('/hello/index2')
+      .expect(200)
+      .expect('Hello');
+
+    return request(app.getHttpServer())
+      .get('/hello/index2?l=nl')
+      .expect(200)
+      .expect('Hallo');
+  });
+
+  afterAll(async () => {
+    await app.close();
+  });
+});