Babel 7 #16297
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Babel 7 #16297
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React: size: -0.4%, gzip: -0.2% ReactDOM: size: -0.7%, gzip: -0.7% Details of bundled changes.Comparing: d77c623...348fae3 react
react-dom
react-art
react-native-renderer
react-test-renderer
eslint-plugin-react-hooks
react-events
react-reconciler
create-subscription
Generated by 🚫 dangerJS |
…ere being imported
SimenB
reviewed
Aug 7, 2019
package.json
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| "babel-plugin-check-es2015-constants": "^6.5.0", | ||
| "babel-plugin-external-helpers": "^6.22.0", | ||
| "babel-plugin-syntax-dynamic-import": "^6.18.0", | ||
| "babel-jest": "^24.8.0", |
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you can remove babel-jest entirely, it's not used
acdlite
reviewed
Aug 7, 2019
babel.config.js
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| 'use strict'; | ||
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| module.exports = { | ||
| presets: ['@babel/preset-react', '@babel/preset-flow'], |
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Can we remove these presets and use the plugins directly? That way unexpected stuff can't sneak in.
acdlite
reviewed
Aug 7, 2019
| describe('ReactFreshBabelPlugin', () => { | ||
| beforeEach(() => { |
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The reason Fresh throws an error if you're not in development environment is because the production build of React does not support hot reloading. React uses a process.env.NODE_ENV check (that's what __DEV__ compiles to), not BABEL_ENV. Technically, BABEL_ENV and NODE_ENV could be different, even though they're usually the same.
We should use __DEV__/NODE_ENV since that's what determines the version of React DOM.
if (__DEV__) {
// The tests
} else {
it('throw error if environment is not development', ...);
}
acdlite
reviewed
Aug 8, 2019
babel.config.js
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| plugins: [ | ||
| '@babel/plugin-syntax-jsx', | ||
| '@babel/plugin-transform-react-jsx', | ||
| '@babel/plugin-transform-react-display-name', |
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Let's remove this one. Don't need it.
acdlite
approved these changes
Aug 8, 2019
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Nice work @lunaruan ! |
gaearon
reviewed
Aug 9, 2019
| // fail due to obsolete snapshots | ||
| process.env.NODE_ENV === 'development' | ||
| ? '<rootDir>/packages/react-refresh/src/__tests__/ReactFreshBabelPluginProd-test.js' | ||
| : '<rootDir>/packages/react-refresh/src/__tests__/ReactFreshBabelPlugin-test.js', |
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This is kinda hacky. Can we figure out another way without making exceptions at this level?
gaearon
reviewed
Aug 9, 2019
| @@ -134,12 +134,26 @@ const bundles = [ | |||
| entry: 'react-dom/server.browser', | |||
| global: 'ReactDOMServer', | |||
| externals: ['react'], | |||
| babel: opts => | |||
| Object.assign({}, opts, { | |||
| // Include JSX | |||
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The comment doesn't match the intention.
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I would merge this first #15037 |
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For #12548
Upgraded from Babel 6 to Babel 7.
The only significant change seems to be the way
@babel/plugin-transform-classeshandles classes differently frombabel-plugin-transform-es2015-classes. In regular mode, the former injects a_createClassfunction that increases the bundle size, and in the latter it removes the safeguard checks. However, this is okay because we don't all classes in new features, and we want to deprecate class usage in the future in the react repo.Differences between classes in Babel 6 (left) and Babel 7 (right)
Example diffs (6 on the left and 7 on the right):
ReactDOM-prod.js (facebook-www)
ReactDOM-dev.js (facebook-www)
react-dom.development.js (UMD)
react-dom.production.js (UMD)
react-dom.development.js (CommonJS)
react-dom.production.js (CommonJS)
react-dom-server.node.production.min.js (CommonJS)
react-dom-server.browser.production.min.js (UMD)