fix: improve error handling. closes #336

Author: satya164

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

@@ -747,4 +747,22 @@ yargs
   .command('$0 <name>', 'create a react native library', args, create)
   .demandCommand()
   .recommendCommands()
+  .fail((message, error) => {
+    console.log('\n');
+
+    if (error) {
+      console.log(kleur.red(error.message));
+      throw error;
+    }
+
+    if (message) {
+      console.log(kleur.red(message));
+    } else {
+      console.log(
+        kleur.red(`An unknown error occurred. See '--help' for usage guide.`)
+      );
+    }
+
+    process.exit(1);
+  })
   .strict().argv;

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

@@ -56,14 +56,26 @@ export default async function generateExampleApp({
       : // `npx create-expo-app example --no-install`
         ['create-expo-app@latest', directory, '--no-install'];
 
-  const child = spawn('npx', args, {
-    cwd: dest,
-    env: { ...process.env, npm_config_yes: 'true' },
-  });
-
   await new Promise((resolve, reject) => {
+    const child = spawn('npx', args, {
+      cwd: dest,
+      env: { ...process.env, npm_config_yes: 'true' },
+    });
+
+    let stderr = '';
+
+    child.stderr?.setEncoding('utf8');
+    child.stderr?.on('data', (data) => {
+      stderr += data;
+    });
+
     child.once('error', reject);
     child.once('close', resolve);
+    child.once('exit', (code) => {
+      if (code === 1) {
+        reject(new Error(stderr));
+      }
+    });
   });
 
   // Remove unnecessary files and folders