Preface
Often in front-end interviews or communicating with other colleagues, when it comes to constructing the method of defining a constructor in JS, it is best to use a prototype: define the method The advantage of going to the prototype of the constructor is that the methods of the instance generated by the constructor all point to the index of a function, which can save memory.
This article mainly introduces to you the relevant content about Js using prototype custom array method, and shares it for your reference and study. I won’t say much below, let’s take a look at the detailed introduction.
Question
How to implement the following code:
[1,2,3,4,5].duplicator(); // [1,2,3,4,5,1,2,3,4,5]
Solution
Use the prototype attribute of array and customize the duplicator() method. The js code is as follows:
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Document</title>
<style></style>
<script src="http://apps.bdimg.com/libs/jquery/2.1.4/jquery.min.js" type="text/javascript"></script>
</head>
<body>
<script>
Array.prototype.duplicator = function() {
let s = this.concat(this)
return s
}
let t = [1,2,3,4,5].duplicator()
console.log(t)
</script>
</body>
</html>The display effect on the console is as follows:
Notes
When writing this codeArray.prototype.duplicatorBe careful not to add any brackets. This inside the function refers to the object that calls this method, which is array.
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