PHP's is_array in JavaScript

module.exports = functionis_array (mixedVar) { // eslint-disable-line camelcase
//  discuss at: https://locutus.io/php/is_array/
// original by: Kevin van Zonneveld (https://kvz.io)
// improved by: Legaev Andrey
// improved by: Onno Marsman (https://twitter.com/onnomarsman)
// improved by: Brett Zamir (https://brett-zamir.me)
// improved by: Nathan Sepulveda
// improved by: Brett Zamir (https://brett-zamir.me)
// bugfixed by: Cord
// bugfixed by: Manish
// bugfixed by: Brett Zamir (https://brett-zamir.me)
//      note 1: In Locutus, javascript objects are like php associative arrays,
//      note 1: thus JavaScript objects will also
//      note 1: return true in this function (except for objects which inherit properties,
//      note 1: being thus used as objects),
//      note 1: unless you do ini_set('locutus.objectsAsArrays', 0),
//      note 1: in which case only genuine JavaScript arrays
//      note 1: will return true
//   example 1: is_array(['Kevin', 'van', 'Zonneveld'])
//   returns 1: true
//   example 2: is_array('Kevin van Zonneveld')
//   returns 2: false
//   example 3: is_array({0: 'Kevin', 1: 'van', 2: 'Zonneveld'})
//   returns 3: true
//   example 4: ini_set('locutus.objectsAsArrays', 0)
//   example 4: is_array({0: 'Kevin', 1: 'van', 2: 'Zonneveld'})
//   returns 4: false
//   example 5: is_array(function tmp_a (){ this.name = 'Kevin' })
//   returns 5: false
const _getFuncName = function (fn) {
const name = (/\W*function\s+([\w$]+)\s*\(/).exec(fn)
if (!name) {
return'(Anonymous)'
    }
return name[1]
  }
const _isArray = function (mixedVar) {
// return Object.prototype.toString.call(mixedVar) === '[object Array]';
// The above works, but let's do the even more stringent approach:
// (since Object.prototype.toString could be overridden)
// Null, Not an object, no length property so couldn't be an Array (or String)
if (!mixedVar || typeof mixedVar !== 'object' || typeof mixedVar.length !== 'number') {
returnfalse
    }
const len = mixedVar.length
    mixedVar[mixedVar.length] = 'bogus'
// The only way I can think of to get around this (or where there would be trouble)
// would be to have an object defined
// with a custom "length" getter which changed behavior on each call
// (or a setter to mess up the following below) or a custom
// setter for numeric properties, but even that would need to listen for
// specific indexes; but there should be no false negatives
// and such a false positive would need to rely on later JavaScript
// innovations like __defineSetter__
if (len !== mixedVar.length) {
// We know it's an array since length auto-changed with the addition of a
// numeric property at its length end, so safely get rid of our bogus element
      mixedVar.length -= 1
returntrue
    }
// Get rid of the property we added onto a non-array object; only possible
// side-effect is if the user adds back the property later, it will iterate
// this property in the older order placement in IE (an order which should not
// be depended on anyways)
delete mixedVar[mixedVar.length]
returnfalse
  }
if (!mixedVar || typeof mixedVar !== 'object') {
returnfalse
  }
const isArray = _isArray(mixedVar)
if (isArray) {
returntrue
  }
const iniVal = (typeofrequire !== 'undefined' ? require('../info/ini_get')('locutus.objectsAsArrays') : undefined) || 'on'
if (iniVal === 'on') {
const asString = Object.prototype.toString.call(mixedVar)
const asFunc = _getFuncName(mixedVar.constructor)
if (asString === '[object Object]' && asFunc === 'Object') {
// Most likely a literal and intended as assoc. array
returntrue
    }
  }
returnfalse
}