'App' is not defined no-undef Search for the keywords to learn more about each error. code example
Example: 'App' is not defined react/jsx-no-undef
// 'App' is not defined react/jsx-no-undef
import App from "./App"; //import into index.js file
// 'App' is not defined react/jsx-no-undef
import App from "./App"; //import into index.js file