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Editor to share with you how js uses the Array.map () method, I believe most people do not know much about it, so share this article for your reference, I hope you can learn a lot after reading this article, let's go to know it!

Array.map ()

The map () method creates a new array by executing a function on each array element.

The map () method does not perform functions on array elements that have no values.

The map () method does not change the original array.

This example multiplies each array value by 2:

Example

Var numbers1 = [45, 4, 9, 16, 25]; var numbers2 = numbers1.map (myFunction); function myFunction (value, index, array) {return value * 2;}

Notice that the function takes three parameters:

Project value

Project index

The array itself

When the callback function only uses the value parameter, you can omit the index and array parameters:

Example

Var numbers1 = [45, 4, 9, 16, 25]; var numbers2 = numbers1.map (myFunction); function myFunction (value) {return value * 2;} these are all the contents of the article "how js uses the Array.map () 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!

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