1.数组去重
- function unique1(arr) {
- return [...new Set(arr)]
- }
- function unique2(arr) {
- var obj = {};
- return arr.filter(ele => {
- if (!obj[ele]) {
- obj[ele] = true;
- return true;
- }
- })
- }
- function unique3(arr) {
- var result = [];
- arr.forEach(ele => {
- if (result.indexOf(ele) == -1) {
- result.push(ele)
- }
- })
- return result;
- }
2.字符串去重
- String.prototype.unique = function () {
- var obj = {},
- str = '',
- len = this.length;
- for (var i = 0; i < len; i++) {
- if (!obj[this[i]]) {
- str += this[i];
- obj[this[i]] = true;
- }
- }
- return str;
- }
- ###### //去除连续的字符串
- function uniq(str) {
- return str.replace(/(\w)\1+/g, '$1')
- }
3.输入一个值,返回其数据类型
- function type(para) {
- return Object.prototype.toString.call(para)
- }
4.找出字符串中第一次只出现一次的字母
- String.prototype.firstAppear = function () {
- var obj = {},
- len = this.length;
- for (var i = 0; i < len; i++) {
- if (obj[this[i]]) {
- obj[this[i]]++;
- } else {
- obj[this[i]] = 1;
- }
- }
- for (var prop in obj) {
- if (obj[prop] == 1) {
- return prop;
- }
- }
- }
5.深拷贝 浅拷贝
- //深克隆(深克隆不考虑函数)
- function deepClone(obj, result) {
- var result = result || {};
- for (var prop in obj) {
- if (obj.hasOwnProperty(prop)) {
- if (typeof obj[prop] == 'object' && obj[prop] !== null) {
- // 引用值(obj/array)且不为null
- if (Object.prototype.toString.call(obj[prop]) == '[object Object]') {
- // 对象
- result[prop] = {};
- } else {
- // 数组
- result[prop] = [];
- }
- deepClone(obj[prop], result[prop])
- } else {
- // 原始值或func
- result[prop] = obj[prop]
- }
- }
- }
- return result;
- }
- // 深浅克隆是针对引用值
- function deepClone(target) {
- if (typeof (target) !== 'object') {
- return target;
- }
- var result;
- if (Object.prototype.toString.call(target) == '[object Array]') {
- // 数组
- result = []
- } else {
- // 对象
- result = {};
- }
- for (var prop in target) {
- if (target.hasOwnProperty(prop)) {
- result[prop] = deepClone(target[prop])
- }
- }
- return result;
- }
- // 无法复制函数
- var o1 = jsON.parse(jsON.stringify(obj1));
6.判断元素有没有子元素
- function hasChildren(e) {
- var children = e.childNodes,
- len = children.length;
- for (var i = 0; i < len; i++) {
- if (children[i].nodeType === 1) {
- return true;
- }
- }
- return false;
- }
7.返回当前的时间(年月日时分秒)
- function getDateTime() {
- var date = new Date(),
- year = date.getFullYear(),
- month = date.getMonth() + 1,
- day = date.getDate(),
- hour = date.getHours() + 1,
- minute = date.getMinutes(),
- second = date.getSeconds();
- month = checkTime(month);
- day = checkTime(day);
- hour = checkTime(hour);
- minute = checkTime(minute);
- second = checkTime(second);
- function checkTime(i) {
- if (i < 10) {
- i = "0" + i;
- }
- return i;
- }
- return "" + year + "年" + month + "月" + day + "日" + hour + "时" + minute + "分" + second + "秒"
- }
8.兼容getElementsByClassName方法
- Element.prototype.getElementsByClassName = Document.prototype.getElementsByClassName = function (_className) {
- var allDomArray = document.getElementsByTagName('*');
- var lastDomArray = [];
- function trimSpace(strClass) {
- var reg = /\s+/g;
- return strClass.replace(reg, ' ').trim()
- }
- for (var i = 0; i < allDomArray.length; i++) {
- var classArray = trimSpace(allDomArray[i].className).split(' ');
- for (var j = 0; j < classArray.length; j++) {
- if (classArray[j] == _className) {
- lastDomArray.push(allDomArray[i]);
- break;
- }
- }
- }
- return lastDomArray;
- }
9.封装自己的forEach方法
- Array.prototype.myForEach = function (func, obj) {
- var len = this.length;
- var _this = arguments[1] ? arguments[1] : window;
- // var _this=arguments[1]||window;
- for (var i = 0; i < len; i++) {
- func.call(_this, this[i], i, this)
- }
- }
10.封装自己的filter方法
- Array.prototype.myFilter = function (func, obj) {
- var len = this.length;
- var arr = [];
- var _this = arguments[1] || window;
- for (var i = 0; i < len; i++) {
- func.call(_this, this[i], i, this) && arr.push(this[i]);
- }
- return arr;
- }
11.封装自己的数组map方法
- Array.prototype.myMap = function (func) {
- var arr = [];
- var len = this.length;
- var _this = arguments[1] || window;
- for (var i = 0; i < len; i++) {
- arr.push(func.call(_this, this[i], i, this));
- }
- return arr;
- }
12.封装自己的数组every方法
- Array.prototype.myEvery = function (func) {
- var flag = true;
- var len = this.length;
- var _this = arguments[1] || window;
- for (var i = 0; i < len; i++) {
- if (func.apply(_this, [this[i], i, this]) == false) {
- flag = false;
- break;
- }
- }
- return flag;
- }
13.封装自己的数组reduce方法
- Array.prototype.myReduce = function (func, initialValue) {
- var len = this.length,
- nextValue,
- i;
- if (!initialValue) {
- // 没有传第二个参数
- nextValue = this[0];
- i = 1;
- } else {
- // 传了第二个参数
- nextValue = initialValue;
- i = 0;
- }
- for (; i < len; i++) {
- nextValue = func(nextValue, this[i], i, this);
- }
- return nextValue;
- }
14.获取url中的参数
- function getWindonHref() {
- var sHref = window.location.href;
- var args = sHref.split('?');
- if (args[0] === sHref) {
- return '';
- }
- var hrefarr = args[1].split('#')[0].split('&');
- var obj = {};
- for (var i = 0; i < hrefarr.length; i++) {
- hrefarr[i] = hrefarr[i].split('=');
- obj[hrefarr[i][0]] = hrefarr[i][1];
- }
- return obj;
- }
15.数组排序
- // 快排 [left] + min + [right]
- function quickArr(arr) {
- if (arr.length <= 1) {
- return arr;
- }
- var left = [],
- right = [];
- var pIndex = Math.floor(arr.length / 2);
- var p = arr.splice(pIndex, 1)[0];
- for (var i = 0; i < arr.length; i++) {
- if (arr[i] <= p) {
- left.push(arr[i]);
- } else {
- right.push(arr[i]);
- }
- }
- // 递归
- return quickArr(left).concat([p], quickArr(right));
- }
- // 冒泡
- function bubbleSort(arr) {
- for (var i = 0; i < arr.length - 1; i++) {
- for (var j = i + 1; j < arr.length; j++) {
- if (arr[i] > arr[j]) {
- var temp = arr[i];
- arr[i] = arr[j];
- arr[j] = temp;
- }
- }
- }
- return arr;
- }
- function bubbleSort(arr) {
- var len = arr.length;
- for (var i = 0; i < len - 1; i++) {
- for (var j = 0; j < len - 1 - i; j++) {
- if (arr[j] > arr[j + 1]) {
- var temp = arr[j];
- arr[j] = arr[j + 1];
- arr[j + 1] = temp;
- }
- }
- }
- return arr;
原文链接:https://www.toutiao.com/a7046259287210918432/