index.js
1.11 KB
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'use strict';
var hasSymbols = require('has-symbols')();
var hasToStringTag = hasSymbols && typeof Symbol.toStringTag === 'symbol';
var regexExec;
var isRegexMarker;
var badStringifier;
if (hasToStringTag) {
regexExec = Function.call.bind(RegExp.prototype.exec);
isRegexMarker = {};
var throwRegexMarker = function () {
throw isRegexMarker;
};
badStringifier = {
toString: throwRegexMarker,
valueOf: throwRegexMarker
};
if (typeof Symbol.toPrimitive === 'symbol') {
badStringifier[Symbol.toPrimitive] = throwRegexMarker;
}
}
var toStr = Object.prototype.toString;
var regexClass = '[object RegExp]';
module.exports = hasToStringTag
// eslint-disable-next-line consistent-return
? function isRegex(value) {
if (!value || typeof value !== 'object') {
return false;
}
try {
regexExec(value, badStringifier);
} catch (e) {
return e === isRegexMarker;
}
}
: function isRegex(value) {
// In older browsers, typeof regex incorrectly returns 'function'
if (!value || (typeof value !== 'object' && typeof value !== 'function')) {
return false;
}
return toStr.call(value) === regexClass;
};