js es6遍历数组中每个对象，取到每个key和value,Object方法

for(let [key,val] of arr.entries()){
    	console.log(key,val)
};

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Object方法获取所有key：
let arr = ["a", "b", "c"];
    console.log(Object.keys(arr));
    //["0", "1", "2"]
    /* Object 对象 */
    let obj = {
            age: 20,
            sex: '男'
        },
    keys = Object.keys(obj);
    console.log(keys);
    //["age", "sex"]

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Object方法获取所有value
var obj = {
        10: 'a',
        1: 'b',
        2: 'c'
    };
    console.log(Object.values(obj));
    // ['b', 'c', 'a']

    var obj1 = {
        0: 'a',
        1: 'b',
        2: 'c'
    };
    console.log(Object.values(obj1));
    // ['a', 'b', 'c']