config-overrides.js

const fs = require('fs')
const path = require('path')
const webpack = require('webpack')

const appDirectory = fs.realpathSync(process.cwd())
const resolveApp = relativePath => path.resolve(appDirectory, relativePath)

// our packages that will now be included in the CRA build step
const appIncludes = [
  resolveApp('src'),
  resolveApp('../src'),
  resolveApp('../node_modules/react-native-vector-icons')
]

module.exports = function override(config, env) {
  // allow importing from outside of src folder
  config.resolve.plugins = config.resolve.plugins.filter(
    plugin => plugin.constructor.name !== 'ModuleScopePlugin'
  )
  config.module.rules[0].include = appIncludes
  config.module.rules[1] = null
  config.module.rules[2].oneOf[1].include = appIncludes
  config.module.rules[2].oneOf[1].options.plugins = [
    require.resolve('babel-plugin-react-native-web'),
    require.resolve('@babel/plugin-proposal-class-properties'),
  ].concat(config.module.rules[2].oneOf[1].options.plugins)
  config.module.rules.push({
    test: /\.ttf$/,
    loader: "url-loader", // or directly file-loader
    include: resolveApp("../../node_modules/react-native-vector-icons"),
  });
  config.module.rules = config.module.rules.filter(Boolean)
  config.plugins.push(
    new webpack.DefinePlugin({ __DEV__: env !== 'production' })
  )
  return config
}