手写一些方法

模拟new方法

function Otaku(name,age) {this.name = name;this.age = age;   this.habit = 'Games'}Otaku.prototype.strength = 60;Otaku.prototype.sayName = function () {console.log("I am " + this.name);};function myNew(fn, ...args) {const obj = Object.create(fn.prototype);const ret = fn.apply(obj, args); // ret有可能为nullreturn typeof ret === "object" ? ret || obj : obj;}const person = myNew(Otaku,'甲',20);console.log(person,'person');

数组去重

  // 数组去重// 使用new set // const uniqueArr = [...new Set(arr)];// const uniqueArr1 = Array.from(new Set(arr));// 使用reducefunction unique(arr) {// 先排序，如果重复，则上一个下标的内容一样let sortArr = arr.sort()return sortArr.reduce((acc, current) => {if (acc[acc.length - 1] !== current) {acc.push(current);}return acc;}, [sortArr[0]]);}// let arr = [1,2,3,3,4,5,5]// let newArr = unique(arr);// console.log(newArr,'newArr');// 使用filterfunction unique1(arr) {return arr.filter((element, index, array) => {return array.indexOf(element) == index;});}

扁平化数组

// 使用reduce扁平化数组const flattenArr = (arr) => {return Array.isArray(arr) ? arr.reduce((prev,current) => {return [...prev,...flattenArr(current)]},[]) : [arr];}const newArr = flattenArr([[1,1],[2,3],12,32,[90]]);console.log(newArr); // [1, 1, 2, 3, 12, 32, 90]