diff --git a/packages/react/index.js b/packages/react/index.js index d79f5d2d9ba..999ead77897 100644 --- a/packages/react/index.js +++ b/packages/react/index.js @@ -1,50 +1,6 @@ 'use strict'; -function testMinificationUsedDCE() { - if (process.env.NODE_ENV === 'development') { - // We expect this method only to be called in production. - throw new Error('This is unreachable'); - } - try { - // use scoped variable for our initial test, in case - // 'top-level' mangling is not enabled. - var source = testMinificationUsedDCE.toString(); - var longVariableName = true; - if (longVariableName && source.match(/longVariableName/g).length === 3) { - // We are not minified. - // This might be a Node environment where DCE is not expected anyway. - return; - } - if (source.match(/toString/g).length !== 2) { - // We always look for two matches: - // The actual occurence and then the call to 'match' - // - // We know for a fact the above line exists so there should be 2 - // matches. - // Therefore the browser gave us invalid source. - return; - } - if (source.match(/unreachable/g).length === 2) { - // We always look for two matches: - // The actual occurence and then the call to 'match' - - // Dead code elimination would have stripped that branch - // because it is impossible to reach in production. - setTimeout(function() { - // Ensure it gets reported to production logging - throw new Error( - 'React is running in production mode, but dead code ' + - 'elimination has not been applied. Read how to correctly ' + - 'configure React for production: ' + - 'https://fburl.com/react-perf-use-the-production-build' - ); - }); - } - } catch (e) {} -} - if (process.env.NODE_ENV === 'production') { - testMinificationUsedDCE(); module.exports = require('./cjs/react.production.min.js'); } else { module.exports = require('./cjs/react.development.js');