ES6数组方法记录

// 父类
        class People/*(理解为ESC5构造函数)*/ {
            constructor(name, age) {
                // 属性
                this.name = name
                this.age = age
            }    // 方法与方法之间无逗号，分号  
            eat() {
                alert(`${this.name} eat something`)
            }
            speak() {
                alert(`My name is ${this.name},age ${this.age}`)
            }
        };
        // 子类，子级想调用父级的方法用 super
        class Student extends People {
            constructor(name, age, number) {
                super(name, age)
                this.number = number
            }
            study() {
                alert(`${this.name} study`)
            }
        }

        let zhang = new People('zhang', 20)
        zhang.eat()

        let xiaohong = new Student('xiaohong',11 , '学号');
        xiaohong.study()    

filter
// 过滤不满足条件的对象, 也可以根据 A中id=== B中id来过滤出不符合的
        let xin = [
            { id: 1, name: "老大" },
            { id: 3, name: "老er" },
            { id: 6, name: "老san" },
            { id: 4, name: "老liu" }
        ];
        xin = xin.filter(a => {
            return a.id > 1 && a.id < 5
        })
        console.log(xin);

        // 移除指定相等的值，返回新数组
        let arr = [1, 2, 3]
        function remove(arr, item) {
            return arr.filter(ele => {
                return ele != item;
            })
        }
        console.log(remove(arr, 1));

        // 获取数组指定类型对象放到新数组
        let products = [
            { name: "cucumber", type: "vegetable" },
            { name: "banana", type: "fruit" },
            { name: "celery", type: "vegetable" },
            { name: "orange", type: "fruit" }
        ];
        let products2 = products.filter(product => {
            return product.type === 'fruit';
        })
        console.log(products2);

readuce
  // 求和
        let arr = [0, 20, 30];
        arr.reduce(function (a, b) {
            return a += b
        }, 0)

        // 把数组对象值传到新数组
        var primaryColors = [
            { color: "red" },
            { color: "yellow" },
            { color: "blue" }
        ];
        var colors = primaryColors.reduce((prevIoUs, primaryColors) => {
            prevIoUs.push(primaryColors.color);
            return prevIoUs;
        }, [])
        console.log(colors);

map
const array1 = [1, 4, 9, 16];
const map1 = array1.map(x => x * 2);
console.log(map1);
// Array [2, 8, 18, 32]

// 将对象数组 某个属性值存到 另一个
let cars = [
    {model:"buick", price:"CHEAP"},
    {model:"BMW",price:"exp"}
]
let prices = cars.map(function(car){ 
    return car.price
})

set
// 去除数组的重复成员 [...new Set(array)]

let arr = [1,1,2,2,3,3,1];
Array.from([...new Set(arr)])

// 字符串去重, 新数组
let arr = [...new Set('ababbc')].join('')
console.log(Array.from(arr));