in packages/babel-preset-react-app/webpack-overrides.js [16:31]
config(config, { source }) {
// Babel Macros are notoriously hard to cache, so they shouldn't be
// https://github.com/babel/babel/issues/8497
// We naively detect macros using their package suffix and add a random token
// to the caller, a valid option accepted by Babel, to compose a one-time
// cacheIdentifier for the file. We cannot tune the loader options on a per
// file basis.
if (macroCheck.test(source)) {
return Object.assign({}, config.options, {
caller: Object.assign({}, config.options.caller, {
craInvalidationToken: crypto.randomBytes(32).toString('hex'),
}),
});
}
return config.options;
},