Add +0 to Array.prototype.indexOf to convert negative zero to positive zero #316
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Chakra seems to do this, but no other impls I can test convert -0 to +0. print("indexOf returns +0: " + (1/[true].indexOf(true, -0) > 0));
print("lastIndexOf returns +0: " + (1/[true].lastIndexOf(true, -0) > 0));chakraindexOf returns +0: true spidermonkeyindexOf returns +0: false d8indexOf returns +0: false nodeindexOf returns +0: false |
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This is the fix discussed last October in tc39/test262#435 (comment). JSC and Nashorn also return +0. |
| @@ -29809,7 +29809,8 @@ | |||
| 1. Let _n_ be ? ToInteger(_fromIndex_). (If _fromIndex_ is *undefined*, this step produces the value 0.) | |||
| 1. If _n_ ≥ _len_, return -1. | |||
| 1. If _n_ ≥ 0, then | |||
| 1. Let _k_ be _n_. | |||
| 1. Let _k_ be _n_ + (*+0*). | |||
| 1. NOTE: Adding a positive zero converts *-0* to *+0*. | |||
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rather than a note, would it make more sense to just have "if n is -0, let k be +0, else let k be n"? Adding +0 to -0 to get +0 seems like an irrelevant implementation detail.
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Okay. I'll also update 20.3.1.15 TimeClip to use an extra step.
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Updated the PR per the review comments, negative zero is now handled with an explicit step. |
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thanks, much clearer imo, LGTM! |
Fixes https://bugs.ecmascript.org/show_bug.cgi?id=4545