Examples of extended array contains methods in JavaScript

This article mainly introduces the JavaScript extension array contains Method example, this article directly gives the realization code, needs the friend may refer to under

JavaScript array has no contains method, sometimes it is inconvenient, the contains method is simple to implement:

The code is as follows:
function contains (a, obj) {
var i = a.length;
while (i--) {
if (a[i] = = obj) {
return true;
}
}
return false;
}
Of course we can also extend the array class, as follows JS
The code is as follows:
Array.prototype.contains = function (obj) {
var i = this.length;
while (i--) {
if (this[i] = = obj) {
return true;
}
}
return false;
}
This makes it easy to use the Contains method:
The code is as follows:
alert ([1, 2, 3].contains (2)); => true
alert ([1, 2, 3].contains (' 2 ')); => false