node_modules/is-regex/index.js


1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49

'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;
	};