Change Array.prototype in ecmascript (javascript)
Question
I am working on an app using node_webkit combining HTML, CSS and JS. In one part of my app I want to update the Array.prototype so that I can access the last element of an array easily. The code for that is:
if (!Array.prototype.last){
Array.prototype.last = function(){
return this[this.length - 1];
};
}
If I run only the js-file that works fine and as expected. If I include that js-file into an HTML document it seems that the prototype of the array stays unchanged and I get the error:
data.last is not a function
Do I have to change something so that I can run my code normally from an HTML file or does that not work at all and I have to take the long way around and access each array with array[array.length - 1]?
The HTML code I use to include the script is:
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="utf-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1">
<link rel="stylesheet" href="../CSS/Cocktails.css">
<title>Cocktails</title>
<script type="text/javascript" src="../JavaScript/Cocktail.js"></script>
</head>
<body>
/* some elements, that don't use the script yet */
</body>
</html>
2 answers
solution1
0 2016-05-31 13:34:22
It sounds like you're not calling the function, you'd want to call it like data.last() where data is some array that you've declared. Here's a JSFiddle of it in action.
solution2
0 2016-05-31 13:36:08
In ES5 you need to use defineProperties in order to modify the Array prototype in an enumberable way:
Following should work,
Object.defineProperties(Array.prototype,
{ last: { value: function() { return this[this.length - 1]; } } });
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