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This article mainly introduces how to use the three points in es6, with a certain reference value, interested friends can refer to, I hope you can learn a lot after reading this article, let the editor take you to understand it.

Usage: 1, merge array, syntax is "[... arr1,... arr2]"; 2, copy array object, syntax is "name= [... array object]"; 3, string to character array, syntax is "[... string object]"; 4, deconstruct variables, syntax is "[variable object,... name] = value".

This tutorial operating environment: windows10 system, ECMAScript version 6. 0, Dell G3 computer.

What is the usage of the three dots in es6

The extension operator (spread) is three dots (... Is a new operator for ES6 that does a lot of things, such as converting an array to a comma-separated sequence of parameters Two types of extension operators for objects and operators for arrays are commonly used in application scenarios.

The functions are as follows:

1. Gets the maximum value of the array.

Routine: Math.max (1, 2, 3)

Written by: Math.max (… Is equivalent to the example above.

two。 Call method

Function sum (a _ r _ b) {console.log (a _ r _ b) / / 5} sum (. [2p _ 3])

The output is as follows:

3. Join array

Var arr1 = [0,1,2]; var arr2 = [3,4,5]; arr1.push (... arr2)

Results the array elements are 0,1,2,3,4,5.

4. Join array

Var arr1 = ['asides,' b']; var arr2 = ['c']; var arr3 = ['dudes,' e']; [... arr1,... arr2,... arr3]

The connected array elements are: a, b, c, d, e

5. The string is converted to a real array

[... 'hello'] / /

The result is:

6. Convert the class array to a real array and remove the weight

[. New Set ([1, 2, 3, 3])] / /

New Set returns an array of classes,... Convert a class array to a real array

7. Extended algorithm

Let map = new Map ([[1, 'one'], [2,' two'], [3, 'three'],]); let arr = [... map.keys ()]; / / [1,2,3]

When writing vue projects, since you don't know how many params there are, you can directly params:param.data or params: {undefined

.. param.data} return axios ({method: param.type, url: value.prefix + param.url + value.postfix, params: {. Param.data / / expand the array}}) Thank you for reading this article carefully. I hope the article "how to use the three points in es6" shared by the editor will be helpful to you. At the same time, I hope you will support it. Pay attention to the industry information channel, more related knowledge is waiting for you to learn!

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