Extended operator of new features in ES6

… The extension operator can convert an array into a comma separated sequence of parameters
Extension operator （spread） Also three points （…）. It's like rest Inverse operation of parameter , Convert an array to a comma separated sequence of parameters , Unpack the array

Basic use
Declare an array

 	const beautifulGirl = [" Xiao Liu "," Xiao Ming "," Xiaolingzi "]
    function myGirl(){
    
        console.log(arguments);
    }
    myGirl(...beautifulGirl)
    //  Print the results :" Xiao Liu "," Xiao Ming "," Xiaolingzi "

application :
Merging of arrays

 const beautifulGirl = [" Xiao Liu "," Xiao Ming "," Xiaolingzi "]
 const cuteBoy = [" Xiao Zhang "," ha-ha "," Fat man "]

The traditional way of merging concat

    const lovers = beautifulGirl.concat(cuteBoy)
    console.log(lovers);
    //  Print the results :[' Xiao Liu ', ' Xiao Ming ', ' Xiaolingzi ', ' Xiao Zhang ', ' ha-ha ', ' Fat man ']

ES6 Expand operator merge :

  	const lovers = [...beautifulGirl,...cuteBoy]
    console.log(lovers);
    // [' Xiao Liu ', ' Xiao Ming ', ' Xiaolingzi ', ' Xiao Zhang ', ' ha-ha ', ' Fat man ']

Clone of array ：

    const xiaoLiu = [" Xiao Liu "," Xiaolingzi "," Xiao Ming "] 
    const Girl = [...xiaoLiu]
    console.log(Girl);
    // Print the results :[' Xiao Liu ', ' Xiaolingzi ', ' Xiao Ming ']

Convert a pseudo array to a real array

    const divs = document.querySelectorAll("div")
    const divArr = [...divs]
    console.log(divArr);
    // [div]