javaScript常用数组方法

   let arr = [1, 2, 23, 444, 5556, 777]
    arr.push(1)
    arr.pop()
    arr.unshift(2)
    arr.shift()
    arr.reverse()
    arr.splice(1,1) //从数组中删除并返回一段特定元素
    arr.filter()//遍历过滤出一个新的子数组，返回条件为true的值
    arr.map()//遍历数组返回一个新数组，返回加工后的值
    console.log(arr.slice(2,4)); //返回特定一段元素，不影响旧数组
    console.log(arr.join());
    function join(arr, code = ',') {
        let str = ''
        for (let i = 0; i < arr.length; i++) {
            str += arr[i] + code
        }
        return str.substring(0, str.length - code.length)
    }
    console.log(join(arr,'---'));

    arr.forEach(r => {
        console.log(r);
    })

    let arr1 = [
        {
            name: "Simba",
            age: 20
        },
        {
            name: "Ace",
            age: 30
        },
        {
            name: "Roger",
            age: 40
        }
    ]

    console.log(arr1.map(r => r.name));
    console.log(arr1.map(r => r.age));

    console.log(arr.filter(r => r % 2 === 0));

    arr = arr.filter(r => {
        return r <= 400
    })
    console.log(arr);

    console.log(arr.some(r => r > 500));

    arr.every(r => r % 2 === 0)