This patch implements automatic on-disk code caching that can be enabled via an environment variable NODE_COMPILE_CACHE=/path/to/cache/dir. When set,

Node v22.1.0 (Current)

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2024-05-02 15:00:02

This patch implements automatic on-disk code caching that can be enabled via an environment variable NODE_COMPILE_CACHE=/path/to/cache/dir.

When set, whenever Node.js compiles a CommonJS or a ECMAScript Module, it will use on-disk V8 code cache persisted in the specified directory to speed up the compilation. This may slow down the first load of a module graph, but subsequent loads of the same module graph may get a significant speedup if the contents of the modules do not change. Locally, this speeds up loading of test/fixtures/snapshot/typescript.js from ~130ms to ~80ms.

To clean up the generated code cache, simply remove the directory. It will be recreated the next time the same directory is used for NODE_COMPILE_CACHE.

Compilation cache generated by one version of Node.js may not be used by a different version of Node.js. Cache generated by different versions of Node.js will be stored separately if the same directory is used to persist the cache, so they can co-exist.

Caveat: currently when using this with V8 JavaScript code coverage, the coverage being collected by V8 may be less precise in functions that are deserialized from the code cache. It's recommended to turn this off when running tests to generate precise coverage.