即使我在 package.json 中将主入口点更改为 app.js，为什么还需要 index.js？

Question

In my react application I've changed my main entry point from index.js to app.js. But somehow, if I don't import the app.js to my index.js, the program crashes. Is there anyone who know the reason?

Answer 1

in the index.js it searchs for an html element with a specific id most probably app and put it inside the main tag, and in the other hand if you notice that the root component div id is the same id that the index.js tries to search for

Answer 2

if you are using Create React App template then entry for your app is defined as src/index in webpack config by default. check here: https://github.com/facebook/create-react-app/tree/master/packages/react-dev-utils#webpackhotdevclient

Or if you are building your app from scratch then you can set your entry anything else in the webpack config file.

what if you want to change entry point in a create react app ?

at first Eject from CRA . then create your own configuration including webpack