fix(perf): add cache for fs calls when using language service (#908)

[IOuser]

Recently, I encountered the slowdown of tests with disabled jest cache.
As @Farbdose noted in #908 , the reason for the slowdown is intensive work with the file system.
So I tried to implement a simple cache for fs calls in TS language service.

And here's results for my codebase:
Before adding fs cache: ~280s (3 runs avg.)
After adding fs cache: ~91s (3 runs avg.)

Hope it helps.

[coveralls]

Pull Request Test Coverage Report for Build 2443

• 7 of 7 (100.0%) changed or added relevant lines in 1 file are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+0.04%) to 91.974%

---

Totals
Change from base Build 2442:	0.04%
Covered Lines:	920
Relevant Lines:	965

---

💛 - Coveralls

[IOuser]

@kulshekhar, would you please provide your feedback? Thanks

[Farbdose]

@IOuser I wanted to test your fix with my demo repository but for some reason I can't get ts-jest to build. It always fails with src/cli/index.ts:14:33 - error TS2314: Generic type 'Arguments' requires 1 type argument(s). but the CI server doesn't have any problems with it... The tests fail too if I try it, looks like I'm using the wrong version of something fundamental.

Can't I build ts-jest with:

node@8.11.2
npm@5.6.0
typescript@3.1.6

?

Do I need to do something specific after cloning the repository (except npm install && npm run build)?

[IOuser]

@Farbdose, I ran into a similar problem, npm just updates all dependencies as they are not fixed in package.json.
Try to remove node_modules, rollback package-lock.json (if it was updated by npm install) and use npm ci instead npm install.

[Farbdose]

@IOuser many thanks. That looks much cleaner than my own fix:

find . -type f -print0 | xargs -0 sed -i "s/\(argv\|args\|_\).\sArguments\([^<a-zA-Z]\)/\1: Arguments<any>\2/g"

[IOuser]

@Farbdose, did you checkout to add-simple-cache-for-fs-calls branch in ts-jest submodule? I see that npm run compileTsJest produced dist without changes from this PR

[Farbdose]

@IOuser Just realized that too, I was only searching for the word memoize and it was in dist do I didn't look further

Regarding the submodule checkout ... I ... did ... and I may have accidentially added a -b to the checkout command... fixed

Now we are getting somewhere: I have a clear speedup from 45s to 36s in the gitlab CI and 33s on my local SSD.

Branch: add-simple-cache-for-fs-calls
Commit: c3bddefb9725f6ca6164998722f6d9b20abeb3c4
CI Run: JobID:143574563

Thats more or less what I got too with my early hacks in the compiler.js but thats still way to long for an empty test suite. Even if I have some heavy modules.

[Farbdose]

@IOuser new cpu-profile and ts-jest log

I think we are still lossing some time on parsing the contents of the cached package.json files over and over.

[IOuser]

@Farbdose, now I see. In 23.10.0-beta.2 language service was enabled by default (for type checking, const enums, etc..). That's why compile time dramatically increased.
There is option to use old behavior.

[GeeWee]

I'd love to merge this in. We already have lodash.memoize as a dependency, can we use that instead of implementing our own function?

[4kochi]

Hi there, thanks for your great work maintaining this repo. I just want to know what the state of this PR is.
I recently update to the latest version of jest-preset-angular v7, coming from v6. I noticed that the performance is slower then before for non cached tests.

[kulshekhar]

addressed in #1049