// Warn if overriding existing method if(Array.prototype.equals) console.warn("Overriding existing Array.prototype.equals. Possible causes: New API defines the method, there's a framework conflict or you've got double inclusions in your code."); // attach the .equals method to Array's prototype to call it on any array Array.prototype.equals = function (array) { // if the other array is a falsy value, return if (!array) return false; // compare lengths - can save a lot of time if (this.length != array.length) return false; for (var i = 0, l=this.length; i < l; i++) { // Check if we have nested arrays if (this[i] instanceof Array && array[i] instanceof Array) { // recurse into the nested arrays if (!this[i].equals(array[i])) return false; } else if (this[i] != array[i]) { // Warning - two different object instances will never be equal: {x:20} != {x:20} return false; } } return true; } // Hide method from for-in loops Object.defineProperty(Array.prototype, "equals", {enumerable: false}); Array.prototype.matchItems = function (array) { // if the other array is a falsy value, return if (!array) return []; return this.filter(item => array.includes(item)); } // Hide method from for-in loops Object.defineProperty(Array.prototype, "matchItems", {enumerable: false});