phpjs/functions/array/array_key_exists.js

php.js offers community built php functions in javascript

function array_key_exists(key, search) {
  //  discuss at: http://phpjs.org/functions/array_key_exists/
  // original by: Kevin van Zonneveld (http://kevin.vanzonneveld.net)
  // improved by: Felix Geisendoerfer (http://www.debuggable.com/felix)
  //   example 1: array_key_exists('kevin', {'kevin': 'van Zonneveld'});
  //   returns 1: true

  if (!search || (search.constructor !== Array && search.constructor !== Object)) {
    return false;
  }

  return key in search;
}