前端面试笔试题总结

1.取出两个数组的不同元素

let a1 = [1, 3, 5, 6];

let a2 = [2, 3, 4, 6];

let arr = a1.concat(a2).filter((v, i, arr) => {

　　return arr.indexOf(v) === arr.lastIndexOf(v);

});

console.log(arr);  //[1, 5, 2, 4]

2.取出两个数组的相同元素

// 方法一
let a1 = [1, 3, 5, 6];
let a2 = [2, 3, 4, 6];

let arr = a1.concat(a2).filter((v, i, arr) => {
    return arr.indexOf(v) !== arr.lastIndexOf(v);
});
arr = [...new Set(arr)];
console.log(arr);    // [3, 6]

// 方法二
let arr = [];
a1.forEach(v => {
    if (a2.includes(v)) {
        arr.push(v);
    }
});
console.log(arr);   // [3, 6]

3.创建数组[0, 1, 2, 3, 4, 6, 7, 8, 9]

let arr = Array.from(new Array(10), (v, i) => i);
[...new Array(10).keys()];