本文给大家介绍开发时候常用到的的js方法封装，有一定的参考价值，有需要的朋友可以参考一下，希望对你们有所帮助。
1、判断是否是一个数组
function isarray(arr){return object.prototype.tostring.call(arr) ==='[object array]';} isarray([1,2,3]) //true
2、判断是否是一个函数(三种)
function isfunction(fn) {return object.prototype.tostring.call(fn) ==='[object function]';return fn.constructor == function;return fn instanceof function;return typeof (fn) == function;}
3、数组去重，只考虑数组中元素为数字或者字符串
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、动态去重
var arr = [1,2, 3, 4];function add() {var newarr = [];$('.addele').click(() => {var rnd = math.ceil(math.random() * 10);newarr.push(rnd)for (var i =0; i < newarr.length; i++) {if (arr.indexof(newarr[i]) == -1) {arr.push(newarr[i])arr.sort(function (a, b) {return b - a //降序});}}console.log(arr)//[1,2,3,4,5,6,7,8,9]})}add()
5、去除字符串空格(包含三种情况)
function trim(str) {return str.replace(/^[" "||"　"]*/,"").replace(/[" "|"　"]*$/,"");// 去除头和尾return str.replace(/\s/g,'');//去除所有空格return str.replace(/(\s*$)/g,"");//去除右边所有空格}
6、判断是否为邮箱地址
function isemail(emailstr) {var reg = /^[a-za-z0-9]+([._-]*[a-za-z0-9]*)*@[a-za-z0-9]+.[a-za-z0-9{2,5}$]/;var result = reg.test(emailstr);if (result) {alert("ok");} else {alert("error");}}
7、判断是否是手机号
function ismobilephone(phone) {var reg = /^1\d{10}$/;if (reg.test(phone)) {alert('ok');} else {alert('error');}}
8、获取一个对象里面第一次元素的数量
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) //2
9、获取元素相对于浏览器窗口的位置，返回一个{x,y}对象
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、判断某个字母在字符串中出现的次数
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) //4
11、计算出数组中出现次数最多的元素
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、数组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 对象（第一种）
//第一种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;};//第二种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'){//判断原型链target[prop] = (tostr.call(origin[prop]) == arrstr) ? [] : {}//判断obj的key是否是数组deepclone(origin[prop],target[prop]);//递归的方式}else{target[prop] = origin[prop];}}}return target}deepclone(obj,newobj);console.log(newobj)
15、求数组最大值和最小值
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数组去重
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、对比两个数组，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、数组和对象比较。取出对象的key和数组元素相同的
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、删除数组中某个元素
//第一种array.prototype.remove = function(val){var index = this.indexof(val);if(index !=0){this.splice(index,1)}}[1,3,4].remove(3)//第二种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、判断数组是否包含某个元素
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
总结：以上就是本篇文的全部内容，希望能对大家的学习有所帮助。更多相关教程请访问javascript视频教程！
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以上就是开发时候常用到的的js方法封装（总结）的详细内容。