Javascript: check if the given element is in array

in_array.js

function in_array(value, array) {
	if (array.constructor !== Array)
		return false;
	
	return array.filter(function(item) { return item == value; }).length > 0;
}

// example

in_array(2, [1,2,3, "foo", "bar"]); // true

// ----------------------------------------------------------------------------------------------------------------------

// extending Array prototype

Object.defineProperty(Array.prototype, 'in_array', {
	value: function(value) {
		return this.filter(function(item) { return item == value; }).length > 0
	},
	writable: false,
	configurable: false,
	enumerable: true
});

// Exemple

[1,2,3, "foo", "bar"].in_array(2); // true