Create React App override for start script using rewire library

start.js

const path = require('path');
const rewire = require('rewire');

process.chdir(path.join(__dirname, '..'));

const start = rewire('react-scripts/scripts/start.js')
const configFactory = start.__get__('configFactory');
const configFactoryMock = (webpackEnv) => {
    const config = configFactory(webpackEnv);

    // display errors for child compilations
    config.stats = {
        ...config.stats,
        children: true
    };

    return config;
}

start.__set__('configFactory', configFactoryMock);