feat: add support for expo example in native libraries

Author: satya164

packages/create-react-native-library/src/exampleApp/generateExampleApp.ts

@@ -4,6 +4,7 @@ import https from 'https';
 import { spawn } from '../utils/spawn';
 import sortObjectKeys from '../utils/sortObjectKeys';
 import type { TemplateConfiguration } from '../template';
+import dedent from 'dedent';
 
 const FILES_TO_DELETE = [
   '__tests__',
@@ -35,20 +36,24 @@ const PACKAGES_TO_REMOVE = [
   'typescript',
 ];
 
-const PACKAGES_TO_ADD_WEB = {
+const PACKAGES_TO_ADD_EXPO_WEB = {
   '@expo/metro-runtime': '~3.2.1',
   'react-dom': '18.2.0',
   'react-native-web': '~0.18.10',
 };
 
+const PACKAGES_TO_ADD_DEV_EXPO_NATIVE = {
+  'expo-dev-client': '~5.0.3',
+};
+
 export default async function generateExampleApp({
   config,
   destination,
   reactNativeVersion = 'latest',
 }: {
   config: TemplateConfiguration;
   destination: string;
-  reactNativeVersion?: string;
+  reactNativeVersion: string | undefined;
 }) {
   const directory = path.join(destination, 'example');
 
@@ -219,14 +224,39 @@ export default async function generateExampleApp({
       bundledNativeModules = {};
     }
 
-    Object.entries(PACKAGES_TO_ADD_WEB).forEach(([name, version]) => {
-      dependencies[name] = bundledNativeModules[name] || version;
-    });
+    if (config.project.native) {
+      Object.entries(PACKAGES_TO_ADD_DEV_EXPO_NATIVE).forEach(
+        ([name, version]) => {
+          devDependencies[name] = bundledNativeModules[name] || version;
+        }
+      );
+
+      scripts.start = 'expo start --dev-client';
+      scripts.android = 'expo run:android';
+      scripts.ios = 'expo run:ios';
+
+      delete scripts.web;
 
-    scripts.web = 'expo start --web';
+      await fs.writeFile(
+        path.join(directory, '.gitignore'),
+        dedent`
+        # These folders are generated with prebuild (CNG)
+        android/
+        ios/
+        `
+      );
+    } else {
+      Object.entries(PACKAGES_TO_ADD_EXPO_WEB).forEach(([name, version]) => {
+        dependencies[name] = bundledNativeModules[name] || version;
+      });
+
+      scripts.web = 'expo start --web';
+    }
 
     const app = await fs.readJSON(path.join(directory, 'app.json'));
 
+    app.expo.name = `${config.project.name} Example`;
+    app.expo.slug = `${config.project.slug}-example`;
     app.expo.android = app.expo.android || {};
     app.expo.android.package = `${config.project.package}.example`;
     app.expo.ios = app.expo.ios || {};

packages/create-react-native-library/src/index.ts

@@ -103,9 +103,9 @@ async function create(_argv: yargs.Arguments<Args>) {
     spinner.text = 'Generating example app';
 
     await generateExampleApp({
+      config,
       destination: folder,
       reactNativeVersion: answers.reactNativeVersion,
-      config,
     });
   }
 

packages/create-react-native-library/src/input.ts

@@ -57,6 +57,12 @@ const LANGUAGE_CHOICES: {
 
 const EXAMPLE_CHOICES = (
   [
+    {
+      title: 'App with Expo CLI',
+      value: 'expo',
+      description: 'managed expo app for easier upgrades',
+      disabled: false,
+    },
     {
       title: 'App with Community CLI',
       value: 'vanilla',
@@ -71,12 +77,6 @@ const EXAMPLE_CHOICES = (
       // Codegen spec shipping is implemented
       disabled: !process.env.CRNL_ENABLE_TEST_APP,
     },
-    {
-      title: 'App with Expo CLI',
-      value: 'expo',
-      description: 'managed expo app with web support',
-      disabled: false,
-    },
   ] as const
 ).filter((choice) => !choice.disabled);
 
@@ -304,10 +304,15 @@ export async function createQuestions({
         }
 
         return EXAMPLE_CHOICES.filter((choice) => {
-          if (values.type) {
-            return values.type === 'library'
-              ? choice.value === 'expo'
-              : choice.value !== 'expo';
+          if (values.type === 'library') {
+            return choice.value === 'expo';
+          }
+
+          if (
+            values.type === 'legacy-module' ||
+            values.type === 'legacy-view'
+          ) {
+            return choice.value !== 'expo';
           }
 
           return true;

packages/create-react-native-library/src/template.ts

@@ -71,9 +71,9 @@ const EXAMPLE_MODULE_NEW_FILES = path.resolve(
   '../templates/example-module-new'
 );
 const EXAMPLE_VIEW_FILES = path.resolve(__dirname, '../templates/example-view');
+const EXAMPLE_EXPO_FILES = path.resolve(__dirname, '../templates/example-expo');
 
 const JS_FILES = path.resolve(__dirname, '../templates/js-library');
-const EXPO_FILES = path.resolve(__dirname, '../templates/expo-library');
 const CPP_FILES = path.resolve(__dirname, '../templates/cpp-library');
 const NATIVE_COMMON_FILES = path.resolve(
   __dirname,
@@ -228,14 +228,18 @@ export async function applyTemplates(
 
   if (answers.languages === 'js') {
     await applyTemplate(config, JS_FILES, folder);
-    await applyTemplate(config, EXPO_FILES, folder);
+    await applyTemplate(config, EXAMPLE_EXPO_FILES, folder);
   } else {
     await applyTemplate(config, NATIVE_COMMON_FILES, folder);
 
     if (config.example !== 'none') {
       await applyTemplate(config, NATIVE_COMMON_EXAMPLE_FILES, folder);
     }
 
+    if (config.example === 'expo') {
+      await applyTemplate(config, EXAMPLE_EXPO_FILES, folder);
+    }
+
     if (config.project.moduleConfig === 'nitro-modules') {
       await applyTemplate(config, NATIVE_FILES['module_nitro'], folder);
       return;

packages/create-react-native-library/templates/expo-library/example/babel.config.js renamed to packages/create-react-native-library/templates/example-expo/example/babel.config.js

@@ -1,8 +1,20 @@
 const path = require('path');
+<% if (example !== 'expo') { -%>
 const pkg = require('../package.json');
+<% } -%>
 <% if (example === 'test-app') { -%>
 const { configureProjects } = require('react-native-test-app');
 <% } -%>
+<% if (example === 'expo') { -%>
+
+// FIXME: `__dirname` is not set correctly in Expo
+// When building the, the cwc is `example/ios`
+// So we override `__dirname` based on that
+// https://github.com/expo/expo/pull/33532
+__dirname = path.resolve(process.cwd(), '..');
+
+const pkg = require(path.join(__dirname, '..', 'package.json'));
+<% } -%>
 
 module.exports = {
 <% if (example === 'test-app') { -%>
@@ -15,7 +27,7 @@ module.exports = {
       automaticPodsInstallation: true,
     },
   }),
-<% } else { -%>
+<% } else if (example === 'vanila') { -%>
   project: {
     ios: {
       automaticPodsInstallation: true,