es6

// 去重复
Array.from(new Set([1, 1, 2, 3]));         // [1, 2, 3]
console.log(Array.from(new Set([1, 1, 2, 3])));

// 分解字符串
Array.from('hello');                       // ["h", "e", "l", "l", "o"]
console.log(Array.from('hello'));

// 转换为ascill
Array.from('hello', x => x.charCodeAt(0)); // [104, 101, 108, 108, 111]
let ascill = Array.from('hello', x => x.charCodeAt(0));
console.log(ascill, typeof (ascill));


// 获取节点
let divs = document.querySelectorAll('div');
Array.from(divs).forEach(function (node) {
    console.log(node);
});


// 数组合并
let i = [2, 3, 5, 6];
let j = [1, 2, 3, 4];
let k = Array.of('hello', 666, i, j);
console.log(k);
Array.of('hello');      // ["hello"]
Array.of(1, 2, 3);      // [1, 2, 3]
Array.of('blink', 182); // ["blink", 182]


// 替换数组内容
// target = 数组位置(3) ,目标等于start数组位置内(0 ~ array.length-1)
let copyWithin1 = [0, 1, 2, 3, 4].copyWithin(target = 3, start = 0);
console.log('copyWithin1:', copyWithin1);

// target = 数组位置(3) ,目标等于start数组位置内(0 ~ array.length-1),结束位置是4
let copyWithin2 = [0, 1, 2, 3, 4].copyWithin(target = 0, start = 3, end = 4);  // [3, 1, 2, 3, 4]
console.log('copyWithin2:', copyWithin2);



// fill  - 填充
[0, 1, 2, 3, 4].fill(5);                 // [5, 5, 5, 5, 5]
// 第二个以后开始fill填充
[0, 1, 2, 3, 4].fill(5, start = 2);        // [0, 1, 5, 5, 5]
// 第二个开始填充，下标4结束.
[0, 1, 2, 3, 4].fill(5, start = 2, end = 4); // [0, 1, 5, 5, 4]



// 字符串包含 - es6
function startsWithLetterA(e, index, array) {
    // 包含开头内容a  - es6 字符串搜索
    console.log(e, index, array);
    if (e.startsWith('a')) {
        return e;
    }
}
var cuteNames = ['jeff', 'marc', 'addy', 'francois'];
cuteNames.find(startsWithLetterA); // "addy"



// 字符串包含 - 返回下标
function startsWithLetterA(element, index, array) {
    if (element.startsWith('a')) {
        return element;
    }
}
var cuteNames = ['jeff', 'marc', 'addy', 'francois'];

cuteNames.findIndex(startsWithLetterA); // 2

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