jest: Jest 24 is 67% slower than Jest 23.6.0 on the same test suite

Just to say that I’m seeing the same as @CrOrc. Every run of jest with 24.0.0 produces a new jest-transform-cache folder plus new perf-cache and haste-map. Hence every test run takes as long as the first - the cache seems to be ignored. This doesn’t happen with jest 23.6.0.

@mucsi96 The issue with TS being slow may be caused by the order of module extension resolution. By default, Jest searches first for ['js', 'json', 'jsx', 'ts', 'tsx', 'node'] – so TS is supported, but at a performance cost. You can adjust the moduleFileExtensions config, to have ts and tsx at the very beginning, e.g. ['ts', 'tsx', 'js', 'json', 'jsx', 'node'].

However, looking at the source, CRA has its own list, which is not allowed to be overridden: https://github.com/facebook/create-react-app/blob/b96ac6c2c007db85812a6e9c0ec54509019c0fea/packages/react-scripts/config/paths.js#L49-L61. You could try passing it as a flag to the CLI, but not sure about that. I’d try adjusting the list in node_modules, making sure it works faster and then send a PR to CRA with adjusted moduleFileExtensions for TS

I can confirm caching of transformed files are broken.

It’s due to this line (from #5862): https://github.com/facebook/jest/blob/31b81ba37eb779161b6db78aa862c0bcd6465bd5/packages/jest-config/src/normalize.js#L272

Removing it speeds up rerunning the same tests by 300% for me in watch mode.

When we get to the cache key, the entire config serialized as a string is part of the cache name, and that will change for every single invocation of Jest:

https://github.com/facebook/jest/blob/31b81ba37eb779161b6db78aa862c0bcd6465bd5/packages/jest-runtime/src/ScriptTransformer.js#L84

Also wondering where to set the name option - it is not documented on https://jestjs.io/docs/en/configuration.html

Setting it in my jest.config.js did not fix the issue.

PR: #7746

I have tried ['ts', 'tsx', 'js', 'json', 'jsx', 'node'] but it made the execution even slower. Probably due to single React component and test vs. much more build-in modules.

@mucsi96 a big part of that is likely micromatch, which is already known as a performance problem and will be fixed in 25

Any chance of getting a 24.0.1 patch release to fix this? 😃 As it stands we are unable to use 24.0.0 due to the significant perf drop … Thanks!

On Feb 4, 2019 at 3:01 PM, <Dylan Vann (mailto:notifications@github.com)> wrote:

Setting name in my jest.config.js file does significantly speed up runs after the first one, but even after that I’ve found Jest 24 is about 50% slower than Jest 23.

Jest 23: 70s Jest 24: 105s

Both of those times are from a warm start (I ran Jest twice before recording the time).

Unfortunately I can’t share the code. It’s running around 300 test suites, around 3000 tests, and around 300 snapshots.

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Setting name in my jest.config.js file does significantly speed up runs after the first one, but even after that I’ve found Jest 24 is about 50% slower than Jest 23.

Jest 23: 70s
Jest 24: 105s

Both of those times are from a warm start (I ran Jest twice before recording the time).

Unfortunately I can’t share the code. It’s running around 300 test suites, around 3000 tests, and around 300 snapshots.

Edit:

I also have api.cache.using(() => process.env.NODE_ENV) in my babel.config.js, doesn’t seem to help.

workaround is to set name in your config

Sorry, where do we set the name? I only have a single config and it is declared in package.json. Adding a name property inside the jest object didn’t help.

workaround is to set name in your config

To me 24 seems slower when there is a cache available, but about the same as 23 when there is no cache, so it seems like @CrOrc is on to something. Here are my results (ran the tests three times with each config):

23.6.0 - Runs after clearing the cache with --clearCache:

Test Suites: 36 passed, 36 total Tests: 553 passed, 553 total Snapshots: 48 passed, 48 total Time: 64.927s

Test Suites: 36 passed, 36 total Tests: 553 passed, 553 total Snapshots: 48 passed, 48 total Time: 54.173s

Test Suites: 36 passed, 36 total Tests: 553 passed, 553 total Snapshots: 48 passed, 48 total Time: 59.353s

23.6.0 - Runs without clearing the cache:

Test Suites: 36 passed, 36 total Tests: 553 passed, 553 total Snapshots: 48 passed, 48 total Time: 36.196s, estimated 60s

Test Suites: 36 passed, 36 total Tests: 553 passed, 553 total Snapshots: 48 passed, 48 total Time: 32.83s, estimated 33s

Test Suites: 36 passed, 36 total Tests: 553 passed, 553 total Snapshots: 48 passed, 48 total Time: 32.278s

24.0.0 - Runs after clearing the cache with --clearCache:

Test Suites: 36 passed, 36 total Tests: 553 passed, 553 total Snapshots: 48 passed, 48 total Time: 56.718s

Test Suites: 36 passed, 36 total Tests: 553 passed, 553 total Snapshots: 48 passed, 48 total Time: 64.682s

Test Suites: 36 passed, 36 total Tests: 553 passed, 553 total Snapshots: 48 passed, 48 total Time: 61.646s

24.0.0 - Runs without clearing the cache:

Test Suites: 36 passed, 36 total Tests: 553 passed, 553 total Snapshots: 48 passed, 48 total Time: 42.998s

Test Suites: 36 passed, 36 total Tests: 553 passed, 553 total Snapshots: 48 passed, 48 total Time: 44.611s

Test Suites: 36 passed, 36 total Tests: 553 passed, 553 total Snapshots: 48 passed, 48 total Time: 48.576s

For me the Jest keeps writing new jest-transform-cache folder on every jest run.

System:
OS: Windows 7
CPU: (8) x64 Intel® Core™ i7-2600 CPU @ 3.40GHz
Binaries:
Node: 11.7.0 - C:\Program Files\nodejs\node.EXE
Yarn: 1.13.0 - ~\scoop\apps\yarn\current\Yarn\bin\yarn.CMD npm: 6.5.0 - C:\Program Files\nodejs\npm.CMD