Keycodes: improve tree shaking by annotating exports as pure #67615
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jsnajdr
added
[Type] Build Tooling
youknowriad
reviewed
Dec 5, 2024
| modifiers, | ||
| ( /** @type {WPModifier} */ modifier ) => { | ||
| export const rawShortcut = | ||
| /* @__PURE__ */ |
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Is this something supported by all bundlers?
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Not sure if it's supported by all, but generally, most would support it, as it's declared in the spec:
https://github.com/javascript-compiler-hints/compiler-notations-spec/blob/main/pure-notation-spec.md
also see compatibility table:
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The webpack + Terser combo also supports it. Webpack adds the comment to code that is pure (typically re-exports) and then Terser uses the comment to eliminate the dead code.
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The following accounts have interacted with this PR and/or linked issues. I will continue to update these lists as activity occurs. You can also manually ask me to refresh this list by adding the If you're merging code through a pull request on GitHub, copy and paste the following into the bottom of the merge commit message. To understand the WordPress project's expectations around crediting contributors, please review the Contributor Attribution page in the Core Handbook. |
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Size Change: 0 B Total Size: 1.83 MB ℹ️ View Unchanged
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tyxla
reviewed
Dec 5, 2024
I never heard about such a feature or plugin. Also, it's not enough that |
That said, I believe another approach to work around the issue would be to move each of these exports into its own module, and then re-export them all from this one. Since we already have the |
Yes, that should also solve the problem, but it's a lot of work, there are many modules and they are tiny and interdependent. We could connect that with a TypeScript rewrite. |
youknowriad
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Dec 5, 2024
michalczaplinski
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Dec 5, 2024
Co-authored-by: jsnajdr <[email protected]> Co-authored-by: youknowriad <[email protected]> Co-authored-by: tyxla <[email protected]> Co-authored-by: sgomes <[email protected]>
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The
keycodespackage has a few exports whose values are result of a function call:The problem with this is that bundlers like esbuild cannot tree shake this code when the
rawShortcutexport is unused. Because the bundler doesn't know ifmapValueshas any side effects.The esbuild docs recommend using a
/* @__PURE__ */comment:They also recommend using an IIFE but in our case the expression is already a
mapValuesfunction call, so we don't need to wrap it.The packages has the
sideEffects: falseflag inpackage.jsonbut it doesn't help here.How to test:
This is very visible in the
packages/dataviews/build-wp/index.jsbundle. The only thing that the bundle uses fromkeycodesis theESCAPEconstant. But the bundle contains also all the code with possible side effects.After this PR, the definition of
ESCAPEis all that remains fromkeycodes.It would be nice to also test this with webpack, but I didn't do that yet.