JScript / JavaScript Extension Feature

Array.At(exp)

Find an entry in an array by value.

Array.prototype.At = function (value) {
	var i;
	for (i=0; i < this.length; i++) {
		if (this[i] === value) {
			return i;
			}
		}
	return -1;
	};

See also:

• https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/indexOf ECMASCRIPT 5.1 added .indexOf() for arrays.

  array.indexOf(value)
  

• https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/includes ECMASCRIPT2016 adds .includes().

  array.includes(value)
  

• https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/find ECMASCRIPT2015 adds the .find() method; useful for more complex comparisons. E.g. searching an array of objects for one with a matching property.

   array.find( function(i,v) {return v.value === value;} )