tenebrous-dicebot/api/node_modules/is-regex/index.js

60 lines
1.4 KiB
JavaScript

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