60 lines
1.4 KiB
JavaScript
60 lines
1.4 KiB
JavaScript
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'use strict';
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var callBound = require('call-bind/callBound');
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var hasSymbols = require('has-symbols')();
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var hasToStringTag = hasSymbols && typeof Symbol.toStringTag === 'symbol';
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var has;
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var $exec;
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var isRegexMarker;
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var badStringifier;
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if (hasToStringTag) {
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has = callBound('Object.prototype.hasOwnProperty');
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$exec = callBound('RegExp.prototype.exec');
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isRegexMarker = {};
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var throwRegexMarker = function () {
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throw isRegexMarker;
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};
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badStringifier = {
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toString: throwRegexMarker,
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valueOf: throwRegexMarker
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};
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if (typeof Symbol.toPrimitive === 'symbol') {
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badStringifier[Symbol.toPrimitive] = throwRegexMarker;
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}
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}
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var $toString = callBound('Object.prototype.toString');
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var gOPD = Object.getOwnPropertyDescriptor;
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var regexClass = '[object RegExp]';
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module.exports = hasToStringTag
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// eslint-disable-next-line consistent-return
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? function isRegex(value) {
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if (!value || typeof value !== 'object') {
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return false;
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}
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var descriptor = gOPD(value, 'lastIndex');
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var hasLastIndexDataProperty = descriptor && has(descriptor, 'value');
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if (!hasLastIndexDataProperty) {
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return false;
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}
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try {
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$exec(value, badStringifier);
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} catch (e) {
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return e === isRegexMarker;
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}
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}
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: function isRegex(value) {
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// In older browsers, typeof regex incorrectly returns 'function'
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if (!value || (typeof value !== 'object' && typeof value !== 'function')) {
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return false;
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}
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return $toString(value) === regexClass;
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};
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