1、判斷是否是一個數(shù)組
function isArray(arr){return Object.prototype.toString.call(arr) ==='[object Array]';} isArray([1,2,3]) //true2、判斷是否是一個函數(shù)(三種)
function isFunction(fn) {return Object.prototype.toString.call(fn) ==='[object Function]';return fn.constructor == Function;return fn instanceof Function;return typeof (fn) == Function;}3、數(shù)組去重,只考慮數(shù)組中元素為數(shù)字或者字符串
function newarr(arr){var arrs = [];for(var i =0;i<arr.length;i++){if(arrs.indexOf(arr[i])== -1){arrs.push(arr[i])}}return arrs;}4、動態(tài)去重
var arr = [1,2, 3, 4];function add() {var newarr = [];$('.addEle').click(() => {var rnd = Math.ceil(Math.random() * 10);newarr.push(rnd)for (var i =0; i < newarr.length; i++) {if (arr.indexOf(newarr[i]) == -1) {arr.push(newarr[i])arr.sort(function (a, b) {return b - a //降序});}}console.log(arr)//[1,2,3,4,5,6,7,8,9]})}add()5、去除字符串空格(包含三種情況)
function trim(str) {return str.replace(/^[" "||" "]*/,"").replace(/[" "|" "]*$/,"");// 去除頭和尾return str.replace(//s/g,'');//去除所有空格return str.replace(/(/s*$)/g,"");//去除右邊所有空格}6、判斷是否為郵箱地址
function isEmail(emailStr) {var reg = /^[a-zA-Z0-9]+([._-]*[a-zA-Z0-9]*)*@[a-zA-Z0-9]+.[a-zA-Z0-9{2,5}$]/;var result = reg.test(emailStr);if (result) {alert("ok");} else {alert("error");}}7、判斷是否是手機(jī)號
function isMobilePhone(phone) {var reg = /^1/d{10}$/;if (reg.test(phone)) {alert('ok');} else {alert('error');}}8、獲取一個對象里面第一次元素的數(shù)量
function getObjectLength(obj){var i=0;for( var attrin obj){if(obj.hasOwnProperty(attr)){i++;}}console.log(i);}var obj = {name:'kob',age:20};getObjectLength(obj) //29、獲取元素相對于瀏覽器窗口的位置,返回一個{x,y}對象
function getPosition(element) {var offsety = 0;offsety += element.offsetTop;var offsetx = 0;offsetx += element.offsetLeft;if (element.offsetParent != null) {getPosition(element.offsetParent);}return { Left: offsetx, Top: offsety };}10、判斷某個字母在字符串中出現(xiàn)的次數(shù)
var str = 'To be, or not to be, that is the question.';var count = 0;var pos = str.indexOf('e');while (pos !== -1) {count++;pos = str.indexOf('e', pos + 1);}console.log(count) //411、計算出數(shù)組中出現(xiàn)次數(shù)最多的元素
var arrayObj = [1,1, 2, 3, 3, 3,4, 5, 5];var tepm = '',count =0;var newarr = new Array();for(var i=0;i<arrayObj.length;i++){if (arrayObj[i] != -1) {temp = arrayObj[i];}for(var j=0;j<arrayObj.length;j++){if (temp == arrayObj[j]) {count++;arrayObj[j] = -1;}}newarr.push(temp + ":" + count);count = 0;}for(var i=0;i<newarr.length;i++){  console.log(newarr[i]);}12、數(shù)組filter(搜索功能)
var fruits = ['apple','banana', 'grapes','mango', 'orange'];function filterItems(query) {return fruits.filter(function(el) {return el.toLowerCase().indexOf(query.toLowerCase()) > -1;})} console.log(filterItems('ap')); // ['apple', 'grapes']13、copy 對象(第一種)
//第一種var cloneObj =function(obj) {var newObj = {};if (obj instanceof Array) {newObj = [];}for (var keyin obj) {var val = obj[key];newObj[key] = typeof val === 'object' ? cloneObj(val) : val;}return newObj;};//第二種function clone(origin , target){var target = target || {};for(var propin origin){target[prop] = origin[prop];}return target;} 14、深度克隆
var newObj ={};function deepClone(origin,target){var target = target || {},toStr = Object.prototype.toString,arrStr = "[object Array]"; for(var propin origin){if(origin.hasOwnProperty(prop)){if(origin[prop] != "null" && typeof(origin[prop]) == 'object'){//判斷原型鏈target[prop] = (toStr.call(origin[prop]) == arrStr) ? [] : {}//判斷obj的key是否是數(shù)組deepClone(origin[prop],target[prop]);//遞歸的方式}else{target[prop] = origin[prop];}}}return target } deepClone(obj,newObj);console.log(newObj)15、求數(shù)組最大值和最小值
Array.prototype.max = function(){return Math.max.apply({},this)} Array.prototype.min = function(){return Math.min.apply({},this)} console.log([1,5,2].max())16、json數(shù)組去重
function UniquePay(paylist){var payArr = [paylist[0]];for(var i =1; i < paylist.length; i++){var payItem = paylist[i];var repeat = false;for (var j =0; j < payArr.length; j++) {if (payItem.name == payArr[j].name) {repeat = true;break;}}if (!repeat) {payArr.push(payItem);}}return payArr;} 17、對比兩個數(shù)組,取出交集
Array.intersect = function () {var result = new Array();var obj = {};for (var i =0; i < arguments.length; i++) {for (var j =0; j < arguments[i].length; j++) {var str = arguments[i][j];if (!obj[str]) {obj[str] = 1;}else {obj[str]++;if (obj[str] == arguments.length){result.push(str);}}//end else}//end for j}//end for ireturn result;}console.log(Array.intersect(["1","2", "3"], ["2","3", "4", "5", "6"]))18、數(shù)組和對象比較。取出對象的key和數(shù)組元素相同的
var arr = ['F00006','F00007','F00008'];var obj = {'F00006':[{'id':21}],'F00007':[{'id':11}]}var newobj = {};for(var itemin obj){if(arr.includes(item)){newobj[item] = obj[item]}}console.log(newObj)19、刪除數(shù)組中某個元素
//第一種Array.prototype.remove = function(val){var index = this.indexOf(val);if(index !=0){this.splice(index,1)}}[1,3,4].remove(3)//第二種function remove(arr, indx) {for (var i =0; i < arr.length; i++) {var index = arr.indexOf(arr[i]);if (indx == index) {arr.splice(index, 1)}}return arr}20、判斷數(shù)組是否包含某個元素
Array.prototype.contains = function (val) {for (var i =0; i < this.length; i++) {if (this[i] == val) {return true;}}return false;}; [1, 2,3, 4].contains(2)//true
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