optimize alias plugin for huge alias objects#438
optimize alias plugin for huge alias objects#438VincentBailly wants to merge 5 commits intowebpack:mainfrom
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| this.source = source; | ||
| this.options = Array.isArray(options) ? options : [options]; | ||
| for (const item of this.options) { | ||
| item.nameWithSlash = item.name + "/"; |
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It's just a memoization so we don't do this concatenation on every resolution, the concatenation creates an object that is short lived, creating work for the garbage collector. By creating the concatenated string once, storing it and reusing it we save the memory overhead of creating many times the same temporary objects.
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If the aliasing object gets truly large, it'd be worth investing in adding a dependency on a prefix-tree implementation that can handle the optional * component in the path, and use that to optimize the matching logic.
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To avoid shape changes it would be best to have this.options consist of fresh objects that have all required properties.
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Tests are failed |
Hoists per-option strings (nameWithSlash, absolutePath, wildcardPrefix/Suffix)
out of the hot AliasPlugin scan into AliasUtils#compileAliasOptions, invoked
once per resolver in AliasPlugin#apply (and in TsconfigPathsPlugin when a
paths map is built). The per-resolve loop then runs with no string concat,
no name.split("*"), and no resolver.join per unmatched entry - the cost that
dominated projects with hundreds of webpack aliases (see #438).
Adds two benchmark cases covering the monorepo-scale scenario:
- huge-alias-list: 300 non-matching + 8 matching aliases, match near end
- huge-alias-miss: 300 aliases + requests that never match any
Local wall-clock numbers (Node 22, tinybench):
before after delta
huge-alias-list 225 ops 405 ops +80%
huge-alias-miss 453 ops 893 ops +97%
large-alias-list 653 ops 856 ops +31%
https://claude.ai/code/session_01ERSdt7j3dKwd9MxNbuuXnm
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The alias plugin gets very slow when the webpack config has many aliases.
This PR aims to re-implement the features of the current alias plugin but in a more efficient manner: