Fix Array.prototype.copyWithin polyfill #2902
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@shicks could you review this one, since polyfills are really your thing? |
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Created internal issue b/122075328 |
brad4d
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internal-issue-created
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@shicks Thanks! I've fixed and commented, please review them. |
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I'm not super familiar with the github code review tools - I marked two conversations as unresolved, so hopefully you'll see my responses now. |
| assertObjectEquals([1, 3, 4, 4, 5], [1, 2, 3, 4, 5].copyWithin(1, 2, -1)); | ||
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| testCopyWithin_throwsIfNullish() { |
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This test no longer passes. Please remove it.
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Really? It should be pass and I believe it passes.
this is null and this.length is referred on the top of the polyfill function, so it should throw an error.
https://github.com/google/closure-compiler/pull/2902/files#diff-a5e0f0788d56ad46f3db1223fd3c8b5cR36
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I didn't look close enough: it fails because the start and target arguments are not optional (unfortunately, I don't think there's a way to run the polyfill tests externally, so there's no way for you to reproduce it). The best you can do is something like this:
Array.prototype.copyWithin.call(null, some_other_array, 0);
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@tjgq understood. It is not a runtime test, but a type check failed. I added the second and the third argument.
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| testCopyWithin_throwIfFailToDeleteProperty() { |
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@tjgq Probably type check in 2nd arg of Object.defineProperty() failed, so I fixed it.
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@tjgq Thanks! 😸 |
Improvement:
thisis null or undefinedAlso this fixes
.nameand.lengthwithdefineProperty.But if the policy of Closure Compiler for them is "won't fix", I will revert them.
I don't know how to run polyfill tests (#1504), but I confirmed this passed all Test262 tests for copyWithin. (https://gist.github.com/teppeis/c8a88f653cdd70ed3e3d6597ec1ee30c)
Ref: