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 = { },前端 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经常字母
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.返回当前的站群服务器时间(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.封装自己的服务器租用数组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;