feat: Improve performance of stack function #1281
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added 3 commits
November 5, 2021 13:29
This one only works if the items are sorted by their start time. So unfortunately it doesn't play nice with custom ordering.
Now the stacking algorithm respects order correctly, while still making a significant improvement to performance.
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Nice work! I'll check this PR today and get it in ASAP |
yotamberk
approved these changes
Nov 6, 2021
yotamberk
changed the title
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🎉 This PR is included in version 7.5.0 🎉 The release is available on: Your semantic-release bot 📦🚀 |
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fixes #1233
Well this was a fun challenge. This PR improves the performance of the stack, substack, and stackSubgroups functions. It also refactors them so that they all use a single common function.
I tested this against a ~1,600 item dataset. Before the change, stacking took 4.6 seconds. After the change it takes 84 milliseconds.
I think the new algorithm is O(n log n) for the best case (order of items matches chronological order) and O(n^2) for the worst case (order of items is the exact inverse of chronological order). I believe the previous stacking algorithm was actually O(n^2 log n), and not the O(n^2) mentioned in yotamberk/timeline-plus#26. But I'm not a computer scientist, so someone else would have to confirm this.
I have tested this using the "subgroups" example and it appears to maintain the same stacking behaviour. I've also tested it with a large dataset in my employer's application and it looks identical there too. But I realise that this isn't exactly extensive testing, so please let me know if there's anything I missed.