Summary:
Uglify@3.1.7 is causing some perf issues (more specifically, this commit: 5b4b07e9a7) that are impacting TTI on RN views and increased memory usage.
More specifically, code like:
```
function nonTrivialFn(pre) {
return pre + Math.random();
}
function hotFunctionCalledALotOfTimes(num) {
return nonTrivialFn(num + Math.random());
}
hotFunctionCalledALotOfTimes(3);
hotFunctionCalledALotOfTimes(5);
```
in v3.1.7 gets converted to:
```
function hotFunctionCalledALotOfTimes(num){
return function(pre) {
return pre + Math.random();
}(num + Math.random())
}
hotFunctionCalledALotOfTimes(3);
hotFunctionCalledALotOfTimes(5);
```
This causes a function creation each time `hotFunctionCalledALotOfTimes` is called.
By comparison, in v3.1.6, that previous code was converted to:
```
function nonTrivialFn(pre){
return pre + Math.random()
}
function hotFunctionCalledALotOfTimes(num){
return nonTrivialFn(num + Math.random())
}
hotFunctionCalledALotOfTimes(3);
hotFunctionCalledALotOfTimes(5);
```
Reviewed By: jeanlauliac, alexeylang
Differential Revision: D6296740
fbshipit-source-id: b3988d886e607103ec3ae6b9763b2f0411a8aa3c
Summary:
`metro-bundler` v0.21 contains a rewritten bundling mechanism, with simplified logic and much faster rebuild times, called delta bundler. This release contains a couple of breaking changes:
* Now, when using a custom transformer, the list of additional babel plugins to apply are passed to the `transform()` method. These are used in non-dev mode for optimization purposes (Check 367a5f5db8 (diff-40653f0c822ac59a5af13d5b4ab31d84) to see how to handle them from the transformer).
* Now, when using a custom transformer outputting `rawMappings`, the transformer does not need to call the `compactMappings` method before returning (check d74685fd1d (diff-40653f0c822ac59a5af13d5b4ab31d84) for more info).
* We've removed support for two config parameters: `postProcessModules` and `postProcessBundleSourcemap`.
Reviewed By: davidaurelio
Differential Revision: D6186035
fbshipit-source-id: 242c5c2a954c6b9b6f339d345f888eaa44704579
Summary:
**Summary**
Minification fails or minified bundle may crash due to uglify-es bugs which have been fixed recently. See https://github.com/facebook/react-native/issues/16689
**Test plan**
Try to production bundle a project using ex-navigation, which fails with:
```
Maximum call stack size exceeded
```
Use this patch and see that bundling suceeds. There are also minified runtime errors solved by this change, see https://github.com/facebook/react-native/issues/16689 for more information.
Closes https://github.com/facebook/metro-bundler/pull/85
Reviewed By: mjesun
Differential Revision: D6259177
Pulled By: rafeca
fbshipit-source-id: 55987eb338b06938181c0da74d104d23eeb135b6
Summary:
This diff migrates Metro Bundler from `worker-farm` to `jest-worker`:
* Fully removes the custom patched `worker-farm` fork.
* Removes //a lot// of non-clear Flow types used to cast functions from callbacks to promises.
* Reduces cyclomatic complexity of the `Transformer` class by using `async`/`await`.
* Cleans all additional methods inside `JSTransformer/index.js`, by moving them to a single class and properly scoping them.
**Note:** this diff does not still enable the ability to bind files to workers by using `computeWorkerKey`; this will come at a later stage.
Reviewed By: davidaurelio
Differential Revision: D6247532
fbshipit-source-id: 51259360a5c15117996777a3be74b73b583f595e
Summary: To determine whether segment boundaries are properly covered by async imports rather than requires, we need to get knowledge about it higher up in the stack. This changeset exposes which of the dependencies are async as an array of indices within the `dependencies` array (I'd prefer avoiding duplicating the strings because they could get inconsistent, and I don't want to have 2 separate arrays of names either because we'd have to modify a bunch of stuff across the stack to support that).
Reviewed By: davidaurelio
Differential Revision: D6220236
fbshipit-source-id: 1ee36bc7c59f7f27e089f7771a24c45c8bd57b5d
Summary: Having types in tests ensure that we're testing what the API is supposed to process and not something else. In that case, adding type revealed that we were mistakenly passing strings instead of `Buffer` objects to the transform and optimize functions, but it would still work because `toString` was called over it. Passing proper `Buffer` objects as expected ensures that it doesn't just work with strings, and that the integration of these files in the rest of the application works as expected. This changeset fixes these callsites and add a few invariants here and there. We use `invariant` instead of `expect()` because Flow understands only the former as a type refinement, even though `expect` would also be a form of possible refinement. I don't think it's a big deal.
Reviewed By: davidaurelio
Differential Revision: D6160019
fbshipit-source-id: cbcbb05d7bccf9e1b9f6bb3ea30b0bb2925aef1b
Summary: Here's a good example why Flow "exact types" are useful: there are a few place where we were adding unusused fields in the objects. As these fields end up in JSON files used to communicate with Buck, this can amount to a waste of resources. This changeset make the type exact and removes the unused fields.
Reviewed By: mjesun
Differential Revision: D6159350
fbshipit-source-id: 8cdf29d5729253f119778943ad961eacb8990c04
Summary: This is the last step remaining before enabling the `import()` syntax to use `require.async()` (for now that function is just doing a simple `require()` in behind).
Reviewed By: davidaurelio
Differential Revision: D6147030
fbshipit-source-id: 5cd8ee6cc550816ae3cdea0b457dc2419c99e7a7
Summary:
After checking more deeply, there were still situations where the delta bundler could generate different bundles between runs: when a module is required by two different modules (it has two or more inverse dependencies), that module would not always be inserted after the first inverse dependency in the bundle, which would cause some bundling order discrepancies.
In order to fix that, the bundler now re-traverses synchronously the dependency graph using a DFS traversing algorithm to guarantee the same order. This will add some small runtime overhead (specially when generating the initial bundle), but it's not worrying (from benchmarks in my macbook pro it'll add ~10ms of initial build for every 1000 modules traversed, being this overhead linear).
Reviewed By: mjesun
Differential Revision: D6124993
fbshipit-source-id: 9bc7cb329f01a7860c7d3b52c3376c643ea5cf3b
Summary:
The `formatBanner.js` file is requiring the `wordwrap` package, but it was not defined in the package.json. Somehow this was working before (maybe the package was being downloaded by another depdendency or maybe `formatBanner` was not used).
This fixes https://github.com/facebook/metro-bundler/issues/79
Reviewed By: mjesun
Differential Revision: D6136865
fbshipit-source-id: 722dd61cb936fca893453f4cfc3248718a329779
Summary: This diff fixes https://github.com/facebook/metro-bundler/issues/78 by adding the `runBeforeMainModule` server parameter to the bundler. This is not the cleanest solution, but will be fixed once we use the Delta Bundler for builds from the CLI
Reviewed By: davidaurelio
Differential Revision: D6074469
fbshipit-source-id: 068926ef671d9f897ad9f1bd0540036a97340c00
Rafael Oleza
Caleb Meredith
David Aurelio
Miguel Jimenez Esun
Andreas Amsenius
Jean Lauliac
Jia Li
Avik Chaudhuri