Add a fix for context unmounting, from experimenting with our application #3979
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📊 Tachometer Benchmark ResultsSummaryduration
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jpnelson
commented
Apr 22, 2023
| @@ -25,7 +25,7 @@ export function createContext(defaultValue, contextId) { | |||
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| this.getChildContext = () => ctx; | |||
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| this.shouldComponentUpdate = function (_props) { | |||
| this.shouldComponentUpdate = function(_props) { | |||
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I didn't intend to change the formatting here but it seems as though the precommit hooks are doing that for me. I might have my setup incorrect, or maybe this file just needs these fixes with the config that exists?
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All good, the same happens on my end. I guess somehow a commit sneaked through one PR that didn't apply the prettier formatting from the pre-commit hook.
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Try reinstalling node_modules. We recently upgraded our prettier version so maybe that's the reason for the discrepancy? Either way, no biggie.
> npm ls prettier
preact@10.13.2 C:\code\github\preactjs\preact
└── prettier@2.8.6
marvinhagemeister
approved these changes
Apr 22, 2023
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Love this! It's a clever trick and one of those optimizations where one wonders why nobody thought of that before. I think nobody would say no to a benchmark, but it's totally fine if that's too much work. I'm more than happy to merge the PR as is.
Thank you for filing a PR and for helping to make Preact even better 🙌
JoviDeCroock
approved these changes
Apr 22, 2023
andrewiggins
requested changes
Apr 22, 2023
| subs.splice(subs.indexOf(c), 1); | ||
| // This is a hot path so we want to be careful about how we're removing items from the subscriber array to keep this fast. | ||
| // This is faster than splicing an item out in testing. | ||
| subs[subs.indexOf(c)] = subs.pop(); |
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I think this doesn't work if c is the last element in the array, since it'll reassign the last element back to it's original index. I think we have to do this in two lines.
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oh right, I missed that in my review. Also what happens if there is only one entry in the array?
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We could consider using Set for this if the Array is a pain, or switching to a sparse array (would require a guard on L45).
| @@ -25,7 +25,7 @@ export function createContext(defaultValue, contextId) { | |||
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| this.getChildContext = () => ctx; | |||
|
|
|||
| this.shouldComponentUpdate = function (_props) { | |||
| this.shouldComponentUpdate = function(_props) { | |||
There was a problem hiding this comment.
Try reinstalling node_modules. We recently upgraded our prettier version so maybe that's the reason for the discrepancy? Either way, no biggie.
> npm ls prettier
preact@10.13.2 C:\code\github\preactjs\preact
└── prettier@2.8.6
developit
added a commit
that referenced
this pull request
Apr 25, 2023
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In testing for our application, this ended up being a fair bit faster than how it was during client routing transitions (that is, when unmounting lots of context subscribers)
I don't know if we need a benchmark specifically for having many context subscribers unmount, but that would be the use case that we ran into with this one.