Handle package.json:main correctly on eject.

react-native-scripts/src/scripts/eject.js

@@ -146,6 +146,8 @@ If you have a .babelrc in your project, make sure to change the preset to \`reac
       console.log(chalk.red(e));
     }
 
+    delete pkgJson.main;
+
     // NOTE: exponent won't work after performing a raw eject, so we should delete this
     // it will be a better error message for the module to not be found than for whatever problems
     // missing native modules will cause

react-native-scripts/src/util/exponent.js

@@ -67,6 +67,15 @@ publish it there. See this StackOverflow question for more information:
   process.stdin.pause();
 
   const pkgJson = JSON.parse((await fsp.readFile(path.resolve('package.json'))).toString());
+
+  const entryPoint = `import Exponent from "exponent";
+import App from "../../../../root.js";
+
+Exponent.registerRootComponent(App);
+`;
+  await fsp.writeFile('index.js', entryPoint);
+  pkgJson.main = 'index.js';
+
   delete pkgJson.scripts.start;
   delete pkgJson.scripts.build;
   delete pkgJson.scripts.eject;