Chore: improve performance of :function
selector
#15181
Merged
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Prerequisites checklist
What is the purpose of this pull request? (put an "X" next to an item)
[ ] Documentation update
[ ] Bug fix (template)
[ ] New rule (template)
[ ] Changes an existing rule (template)
[ ] Add autofixing to a rule
[ ] Add a CLI option
[ ] Add something to the core
[x] Other, please explain:
:function
selector is costly because getPossibleTypes doesn't assume that it matches only a particular set of node types, soNodeEventGenerator
runsesquery.matches()
on every node to check if it matches.For example, running
no-shadow-restricted-names
on ESLint's codebase spends ~95% of the time in trying to match unrelated nodes with its"VariableDeclaration, :function, CatchClause"
selector. Note that this isn't observable withTIMING
because it tracks only time spent in visitors.What changes did you make? (Give an overview)
As esquery hardcodes
:function
to only three exact types, I added them as the only possible types for:function
. This improves the performance ofno-shadow-restricted-names
by the said 95%, and will also improve the execution time for any other rule with the:function
selector in tail positions. We're not using that selector much in core rules, but it's used in plugins.Is there anything you'd like reviewers to focus on?
Does this make sense? I don't expect any maintenance problems with this as the meaning of
:function
in esquery is unlikely to change in the foreseeable future.