Improve performance of spliceChangesIntoString#312
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thecrypticace merged 6 commits intomainfrom Aug 15, 2024
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* Improve performance of spliceChangesIntoString * Add test * Add benchmark * Optimize implementation a bit * Tweak benchmarks * Update changelog --------- Co-authored-by: ABuffSeagull <[email protected]>
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The original implementation built strings in reverse because it was logically simpler to reason about however it resulted in a significant performance and memory usage impact on larger strings with lots of changes. This could be seen in Svelte, Liquid, and Angular.
This implementation is based on #311 (thanks @ABuffSeagull) with some additional tweaks which increase performance further. I ran some benchmarks on my M3 Max (12p / 4e) and tested strings of various sizes with a different number of changes:
While we're not likely to run into cases with extra large strings I felt it was still useful to analyze the performance impact in extreme cases so we can be confident that this is not a performance bottleneck for any file (or expression) we're likely to encounter.
Before this PR:
After this PR:
This amounts to roughly a:
So, in the old implementation, longer and longer strings had a much bigger perf impact.
Additionally, this should reduce memory usage by quite a bit but I don't have concrete numbers for that. (Just some small random testing which confirmed that usage was lower)