mirror of
https://github.com/zebrajr/react.git
synced 2026-01-15 12:15:22 +00:00
34092a0f24
* Throw error to warn of mistaken loading of prod + dev React bundles **what is the change?:** Credit to @gaearon for coming up with a clever way to check for this. :) I mainly just did the manual testing and fixed a couple of typos in his idea. I'd like to do a follow-up PR to add a link and a page explaining this issue more and suggesting how to fix it. **why make this change?:** We want to warn for an unfortunate gotcha for the following situation - 1. Wanting to shrink their JS bundle, an engineer runs it through 'uglifyjs' or some other minifier. They assume this will also do dead-code-elimination, but the 'prod' and 'dev' checks are not envified yet and dev-only code does not get removed. 2. Then they run it through browserify's 'envify' or some other tool to change all calls to 'process.env.NODE_ENV' to "production". This makes their code ready to ship, except the 'dev' only dead code is still in the bundle. Their bundle is twice as large as it needs to be, due to the dead code. This was a problem with the old build system before, but with our new build system output it's possible to detect and throw an informative error in this case. **test plan:** 1. run the build in react as usual; `yarn build` 2. manually run 'uglifyjs -mt' on 'build/packages/react/index.js' to simulate mistakenly minifying React before env variables are resolved, which skips dead code elimination. 3. run the fixtures build - `cd fixtures/packaging && node ./build-all.js && serve ../..` 4. Visit just the production browserify fixture - http://localhost:5000/fixtures/packaging/browserify/prod/ 5. You should see the error thrown indicating this problem has occurred. (Flarnie will insert a screenshot) 6. Do the above steps with NO uglifyjs step, and verify that no error is thrown. When there is no minification applied, we don't assume that this mix-up has occurred. (Flarnie will insert a screenshot) **issue:** fixes #9589 * Remove extra 'prod' env. check and add link to docs in error message **what is the change?:** Based on helpful feedback from @gaearon - removed outer check that `process.env.NODE_ENV` is "production" since we are only calling the `testMinification` method inside of another check for "production" environment. - Added an fburl that points to [our current docs on using the production version of React](https://facebook.github.io/react/docs/optimizing-performance.html#use-the-production-build) **why make this change?:** To save an extra layer of conditionals and to make the error message more clear. **test plan:** Same test plan as earlier - 1. run the build in react as usual; yarn build 2. manually run 'uglifyjs -mt' on 'build/packages/react/index.js' to simulate mistakenly minifying React before env variables are resolved, which skips dead code elimination. 3. run the fixtures build - cd fixtures/packaging && node ./build-all.js && serve ../.. 4. Visit just the production browserify fixture - http://localhost:5000/fixtures/packaging/browserify/prod/ You should see the error thrown indicating this problem has occurred. (Flarnie will insert a screenshot in comments on the PR) 6. Do the above steps with NO uglifyjs step, and verify that no error is thrown. When there is no minification applied, we don't assume that this mix-up has occurred. (Flarnie will insert a screenshot in the comments on the PR.) **issue:** https://github.com/facebook/react/issues/9589 * WIP fix and test 'testMinificationUsedDCE' method **what is the change?:** - Instead of looking for one match when having the method inspect it's own source, we look for two matches, because the search itself will be a match. - WIP moving this method into another file and testing it. Next steps: - Figure out why the babel.transform call is not actually minifying the code - Add tests for uglifyjs - Update build process so that this file can be accessed from `packages/react/index.js` **why make this change?:** - We had a bug in the 'testMinification' method, and I thought the name could be more clear. I fixed the code and also changed the name. - In order to avoid other bugs and keep this code working in the future we'd like to add a unit test for this method. Using the npm modules for 'uglifyjs' and 'babel'/'babili' we should be able to actually test how this method will work when minified with different configurations. **test plan:** `yarn test` **issue:** https://github.com/facebook/react/issues/9589 * Add babeli and uglifyjs as dev-only dependencies **what is the change?:** See commit title **why make this change?:** In order to test that we are correctly detecting different minification situations, we are using these modules in a test. **test plan:** NA **issue:** https://github.com/facebook/react/issues/9589 * Fix typo and add 'uglifyjs' tests **what is the change?:** There was a mix-up in the conditional in 'testMinificationUsedDCE' and this fixes it. The great new tests we added caught the typo. :) Next steps: - get the tests for 'babili' working - update build scripts so that this the 'testMinificationUsedDCE' module is available from 'packages/react/index.js' **why make this change?:** We want to modularize 'testMinificationUsedDCE' and test it. This verifies that the method warns when `uglifyjs` is used to minify but dead code elimination is not done, in a production environment. Generally this is a 'gotcha' which we want to warn folks aboug. **test plan:** `yarn test src/shared/utils/__tests__/testMinificationUsedDCE-test.js` **issue:** https://github.com/facebook/react/issues/9589 * Run prettier * var -> const/let * Require specific version of `uglify-js` **what is the change?:** Removed the '^' from the npm package requirement **why make this change?:** I am seeing failures in CI that show `uglify-js` is returning different output there from my local environment. To further debug this I'd like to run CI with the exact same version of `uglify-js` that I am using locally. **test plan:** push and see what CI does **issue:** https://github.com/facebook/react/issues/9589 * Add build step copying testMinificationUsedDCE into build/packages/react/cj **what is the change?:** This is a first step - we still need (I think) to process this file to get it's contents wrapped in an 'iffe'. Added a step to the build script which copies the source file for the 'testMinificationUsedDCE' module into the 'cjs' directory of our react package build. **why make this change?:** We want this module to be available to the 'index.js' module in this build. **test plan:** Will do manual testing once the build stuff is fully set up. **issue:** * Inline 'testMinificationUsedDCE' and remove unit test for now What: - Inlines the 'testMinificationUsedDCE' method into 'packages/react/index.js' - Removes unit test for 'testMinififcationUsedDCE' - Puts dependencies back the way that they were; should remove extra dependencies that were added for the unit test. Why: - It would add complexity to the build process to add another file to the 'build/packages/react/cjs' folder, and that is the only way to pull this out and test it. So instead we are inlining this. * Revert unintentional changes to dependency versions, variable placing **what is the change?:** - We had updated and added some dependencies, but ended up reverting this in a previous commit. The `yarn.lock` and `package.json` needed updated still though. - There is a call to `Function.toString` which we wanted to wrap in a `try/catch` block. **why make this change?:** To remove unrelated dependency changes and increase the safety of the `Function.toString` call. **test plan:** Manual testing again **issue:** https://github.com/facebook/react/issues/9589