How to implement Array.prototype.filter method by js

This article mainly shows you "js how to achieve Array.prototype.filter method", the content is easy to understand, clear, hope to help you solve your doubts, the following let the editor lead you to study and learn "js how to achieve Array.prototype.filter method" this article.

Manually implement the Array.prototype.filter method

The filter () method creates a new array that contains all the elements of the test implemented by the provided function.

Function filter (arr, filterCallback) {/ / first, check whether the passed parameters are correct. If (! Array.isArray (arr) | |! arr.length | | typeof filterCallback! = = 'function') {return [];} else {let result = []; / / every time we call this function, we create a result array / / because we don't want to change the original array. For (let I = 0, len = arr.length; I < len; iTunes +) {/ / check whether the return value of filterCallback is true if (filterCallback (arr [I], I, arr) {/ / if the condition is true, then push the array elements to result.push (arr [I]);}} return result in result / / return the result array}} these are all the contents of the article "how js implements the Array.prototype.filter method". Thank you for reading! I believe we all have a certain understanding, hope to share the content to help you, if you want to learn more knowledge, welcome to follow the industry information channel!