perf(v2): improve dev build time by not overwriting file if possible #2089
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Motivation
Cache-loader compares with mtime
And currently, whenever we run new "docusaurus start", we always overwrite a lot of the generated files for the first time, invalidating cache. The next reload is fine, because we have runtime content hash cache.
We can do better by checking If file already exist but its not in runtime cache hash yet, then we try to calculate the content hash and then compare. This is to avoid unnecessary overwrite and we can reuse old file. Thus, cache-loader wont invalidate.
Have you read the Contributing Guidelines on pull requests?
yes
Test Plan
Before ~7s
My next dev server (second run) went down to ~5s
This is minor improvement, but as more metadata is written, this is gonna improve a lot
Related PRs
(If this PR adds or changes functionality, please take some time to update the docs at https://github.com/facebook/docusaurus, and link to your PR here.)