es6 그룹 확장 노트

6962 단어 es6
Array.of
let array = Array.of(3,4,7,9,11);
console.log('array='+array);//array=[3,4,7,9,11]

let empty = Array.of();
console.log('empty='+empty);//empty=[]

Array.from
//         
**html**

<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>es6title>
head>
<body>
    <p>p1p>
    <p>p2p>
    <p>p3p>
body>
html>
**es6**
let p = document.querySelectorAll('p');
let pArray = Array.from('p');//        
pArray.forEach(function(item){
    console.log(item.textContent);
    /**
     *p1
     *p2
     *p3
     */
})
console.log(Array.from([1,3,5],function(item){return item*2}))
//[2,6,10]

fill
console.log('fill-7',[1,'a',undefined].fill(7));
//fill-7 ⇒ [7,7,7] 
console.log('fill,pos',['a','b','c'].fill(7,1,3));
//fill,pos ⇒ ['a',7,7]

keys
for(let index of ['1','c','ks'].keys()){
    console.log('keys', index);
    /**
     * keys ⇒ 0
     * keys ⇒ 1
     * keys ⇒ 2
     */
}

values
for(let value of ['1','c','ks'].values()){
    console.log('values', value);
    /**
     * values ⇒ 1
     * values ⇒ c
     * values ⇒ ks
     */
}

entries
for(let [index, value] of ['1','c','ks'].entries()){
    console.log('entries', value);
    /**
     * entries ⇒ 0 1
     * entries ⇒ 1 a
     * entries ⇒ 2 ks
     */
}

copyWithin
console.log([1,2,3,4,5].copyWithin(0,3,4));
//[4,2,3,4,5]

find 및 findIndex
console.log([1,2,3,4,5,6].find(function(item){return item>3})):
//4
console.log([1,2,3,4,5,6].findIndex(function(item){return item>3})):
//3

includes
console.log('number',[1,2,NaN].includes(1));
//number ⇒ true
console.log('number',[1,2,NaN].includes(NaN));
//number ⇒ true

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