Build: Enable TypeScript skipDefaultLibCheck #63056
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This skips _checking_ types that are bundled with TypeScript. We should be able to trust these types, so they can be used without checking them. Many packages use the DOM types and this appeared as a hot spot when analyzing the TypeScript build. Adding this configuration should improve TypeScript build performance.
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| @@ -14,6 +14,8 @@ | |||
| "emitDeclarationOnly": true, | |||
| "isolatedModules": true, | |||
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| "skipDefaultLibCheck": true, | |||
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TS doc recommends that we use skipLibCheck instead. Any good reason to prefer skipDefaultLibCheck?
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I noticed that, I'm not sure why they recommend that.
skipLibCheck ensures that the libraries we depend on typecheck. I understand that skipDefaultLibCheck only skips checking bundle libs (like DOM, ES2020, etc.). These libs are bundled with TypeScript and they should be the highest quality.
With other libs that come from other node_modules, it seems best to check their types especially because if we don't check these files, the errors can appear in other projects that have skipLibCheck disabled. We've seen that packages become stale or have conflicting types that we need to address, I dealt with a lot of this recently in #61486 and related PRs.
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Makes sense to me. Seems like TS docs need some love!
Skip checking types that are bundled with TypeScript. We should be able to trust these types, so they can be used without checking. Many packages use the DOM types and this appeared as a hot spot when analyzing the TypeScript build. Adding this configuration should improve TypeScript build performance. --- Co-authored-by: sirreal <jonsurrell@git.wordpress.org> Co-authored-by: tyxla <tyxla@git.wordpress.org>
What?
Enabling this configuration should improve TypeScript build performance with few or no downsides.
Why?
This skips checking types that are bundled with TypeScript. We should
be able to trust these types, so they can be used without checking them.
Many packages use the DOM types and this appeared as a hot spot when
analyzing the TypeScript build.
Adding this configuration should improve TypeScript build performance.
Benchmark
Run
./node_modules/.bin/tsc --build --force, which is a build without caches:branchtrunkThat's a ~10s build improvement on my machine.
Testing Instructions
CI passes.