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fixes #471 #745

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merged 4 commits into from Jan 10, 2020
Merged

fixes #471 #745

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7948175
checks if RegExp[Symbol.replace] substitutes undefined capture groups
Jan 9, 2020
3bfe93c
use wellKnownSymbol util to get symbol key for replace method
Jan 9, 2020
e0a3d42
fixes REGEXP_REPLACE_SUBSTITUTES_UNDEFINED_CAPTURE conditional logic
Jan 9, 2020
c7429d1
caches Symbol.replace as constant, uses regexp literal, swaps default…
Jan 10, 2020
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17 changes: 15 additions & 2 deletions packages/core-js/internals/fix-regexp-well-known-symbol-logic.js
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Expand Up @@ -28,6 +28,14 @@ var REPLACE_KEEPS_$0 = (function () {
return 'a'.replace(/./, '$0') === '$0';
})();

// Safari <= 13.0.3(?) substitutes nth capture where n>m with an empty string
var REGEXP_REPLACE_SUBSTITUTES_UNDEFINED_CAPTURE = (function () {
if (RegExp.prototype[wellKnownSymbol('replace')]) {
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I think it would be better to cache wellKnownSymbol('replace') as a constant, for example, REPLACE.

return RegExp.prototype[wellKnownSymbol('replace')].call(/./, 'a', '$0') === '';
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/./[REPLACE]('a', '$0')

}
return false;
})();

// Chrome 51 has a buggy "split" implementation when RegExp#exec !== nativeExec
// Weex JS has frozen built-in prototypes, so use try / catch wrapper
var SPLIT_WORKS_WITH_OVERWRITTEN_EXEC = !fails(function () {
Expand Down Expand Up @@ -75,7 +83,9 @@ module.exports = function (KEY, length, exec, sham) {
if (
!DELEGATES_TO_SYMBOL ||
!DELEGATES_TO_EXEC ||
(KEY === 'replace' && !(REPLACE_SUPPORTS_NAMED_GROUPS && REPLACE_KEEPS_$0)) ||
(KEY === 'replace' && !(REPLACE_SUPPORTS_NAMED_GROUPS && (
REPLACE_KEEPS_$0 || REGEXP_REPLACE_SUBSTITUTES_UNDEFINED_CAPTURE
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A strange logic. Why ||?

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My thinking was that REPLACE_KEEPS_$0 is intended for lte IE11 but IE11 doesn't have the issue that REGEXP_REPLACE_SUBSTITUTES_UNDEFINED_CAPTURE intends to resolve and vice-versa, so the conditional would end up false for both of them?

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It's not something related to specific engines, it's related to specific bugs and implementations of old spec versions. At this moment we have 3 replace-specific criteria - so for me seems logically to use && - REPLACE_SUPPORTS_NAMED_GROUPS && REPLACE_KEEPS_$0 && !REGEXP_REPLACE_SUBSTITUTES_UNDEFINED_CAPTURE.

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@mattclough1 Note that the &&s are wrapped inside !(...), so the polyfill would be applied when at least one of the tests is false

))) ||
(KEY === 'split' && !SPLIT_WORKS_WITH_OVERWRITTEN_EXEC)
) {
var nativeRegExpMethod = /./[SYMBOL];
Expand All @@ -90,7 +100,10 @@ module.exports = function (KEY, length, exec, sham) {
return { done: true, value: nativeMethod.call(str, regexp, arg2) };
}
return { done: false };
}, { REPLACE_KEEPS_$0: REPLACE_KEEPS_$0 });
}, {
REPLACE_KEEPS_$0: REPLACE_KEEPS_$0,
REGEXP_REPLACE_SUBSTITUTES_UNDEFINED_CAPTURE: REGEXP_REPLACE_SUBSTITUTES_UNDEFINED_CAPTURE
});
var stringMethod = methods[0];
var regexMethod = methods[1];

Expand Down
5 changes: 4 additions & 1 deletion packages/core-js/modules/es.string.replace.js
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Expand Up @@ -33,7 +33,10 @@ fixRegExpWellKnownSymbolLogic('replace', 2, function (REPLACE, nativeReplace, ma
// `RegExp.prototype[@@replace]` method
// https://tc39.github.io/ecma262/#sec-regexp.prototype-@@replace
function (regexp, replaceValue) {
if (reason.REPLACE_KEEPS_$0 || (typeof replaceValue === 'string' && replaceValue.indexOf('$0') === -1)) {
if (
!reason.REGEXP_REPLACE_SUBSTITUTES_UNDEFINED_CAPTURE &&
(reason.REPLACE_KEEPS_$0 || (typeof replaceValue === 'string' && replaceValue.indexOf('$0') === -1))
) {
var res = maybeCallNative(nativeReplace, regexp, this, replaceValue);
if (res.done) return res.value;
}
Expand Down