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一些常用Javascript函数
- 删除字符串中的空格
String.prototype.Trim = function()
{
return this.replace(/(^\s*)|(\s*$)/g, "");
}
String.prototype.LTrim = function()
{
return this.replace(/(^\s*)/g, "");
}
String.prototype.RTrim = function()
{
return this.replace(/(\s*$)/g, "");
}
- download下载方法
const download = (url, saveName,callback) =>
{
if (typeof url === 'object' && url instanceof Blob) {
url = URL.createObjectURL(url); // 创建blob地址
}
const aLink = document.createElement('a');
aLink.href = url;
aLink.download = saveName;
aLink.target='_blank';
aLink.click();
if(callback) callback();
};
- object数组去重
let arrayUniqueObject = (arr, keyName) => {
var hash = {};
return arr.reduce(function (item, next) {
if(!next) return ;
hash[next[keyName]] ? '' : hash[next[keyName]] = true && item.push(next);
return item;
}, []);
}
- 日期时间格式化
let formatTime = function (time,str) {
var date = new Date(time),
year = date.getFullYear(),
month = date.getMonth() + 1 ,
day = date.getDate() ,
hour = date.getHours(),
minute = date.getMinutes(),
second = date.getSeconds(),
week = date.getDay(),
weekdays = ["星期日","星期一","星期二","星期三","星期四","星期五","星期六"];
switch (str) { //"YY-MM-DD-HH-MM-SS"
case "HH:MM":
return [hour, minute].map(formatNumber).join(':')
break;
case 'YY-MM-DD': //2000-01-01
return [year, month, day].map(formatNumber).join('-')
break;
case 'MM-DD-ss': //01-01
if(time === formatTime((new Date().getTime()),'YY-MM-DD')){
return '今天';
}else if(time === formatTime((new Date().getTime())+(1000*60*60*24),'YY-MM-DD')){
return '明天';
}else {
return [ month, day].map(formatNumber).join('-')
}
break;
case 'MM-DD': //2000-01-01
return [ month, day].map(formatNumber).join('-')
break;
case 'HH:MM': //2000-01-01
return [hour, minute].map(formatNumber).join(':')
break;
case 'YY.MM.DD HH:MM': // 2000.01.01 02:06
return [year, month, day].map(formatNumber).join('.') + ' ' + [hour, minute].map(formatNumber).join(':')
break;
case 'YY-MM-DD HH:MM': // 2000-01-01 02:06
return [year, month, day].map(formatNumber).join('-') + ' ' + [hour, minute].map(formatNumber).join(':')
break;
case 'YY-MM-DD HH:MM:SS': // 2000-01-01 02:06
return [year, month, day].map(formatNumber).join('-') + ' ' + [hour, minute,second].map(formatNumber).join(':')
break;
case "YY.MM.DD": // 2000.01.01
return [year, month, day].map(formatNumber).join('.')
break;
case "objeact":
return {
year :year ,
month:month,
day :day ,
hour :hour ,
minute:minute,
second:second,
week :week === 0 ?7:week ,
getDay :week,
weekValue:weekdays[week]
}
break;
default:
return [year, month, day].map(formatNumber).join('-') + ' ' + [hour, minute, second].map(formatNumber).join(':')
}
}
- html转解码
var HtmlUtil = {
/*1.用浏览器内部转换器实现html转码*/
htmlEncode:function (html){
//1.首先动态创建一个容器标签元素，如DIV
var temp = document.createElement ("div");
//2.然后将要转换的字符串设置为这个元素的innerText(ie支持)或者textContent(火狐，google支持)
(temp.textContent != undefined ) ? (temp.textContent = html) : (temp.innerText = html);
//3.最后返回这个元素的innerHTML，即得到经过HTML编码转换的字符串了
var output = temp.innerHTML;
temp = null;
return output;
},
/*2.用浏览器内部转换器实现html解码*/
htmlDecode:function (text){
//1.首先动态创建一个容器标签元素，如DIV
var temp = document.createElement("div");
//2.然后将要转换的字符串设置为这个元素的innerHTML(ie，火狐，google都支持)
temp.innerHTML = text;
//3.最后返回这个元素的innerText(ie支持)或者textContent(火狐，google支持)，即得到经过HTML解码的字符串了。
var output = temp.innerText || temp.textContent;
temp = null;
return output;
},
/*3.用正则表达式实现html转码*/
htmlEncodeByRegExp:function (str){
var s = "";
if(str.length == 0) return "";
s = str.replace(/&/g,"&");
s = s.replace(/</g,"<");
s = s.replace(/>/g,">");
s = s.replace(/ /g," ");
s = s.replace(/\'/g,"'");
s = s.replace(/\"/g,""");
return s;
},
/*4.用正则表达式实现html解码*/
htmlDecodeByRegExp:function (str){
var s = "";
if(str.length == 0) return "";
s = str.replace(/&/g,"&");
s = s.replace(/\r?\n/g,"<br />");
s = s.replace(/</g,"<");
s = s.replace(/>/g,">");
s = s.replace(/ /g," ");
s = s.replace(/'/g,"\'");
s = s.replace(/"/g,"\"");
return s;
}
};
- 笛卡尔积（适用于商品规格等）
- 笛卡尔乘积是指在数学中，两个集合X和Y的笛卡尓积，又称直积，表示为X × Y，第一个对象是X的成员而第二个对象是Y的所有可能有序对的其中一个成员 。
- 假设集合A={a, b}，集合B={0, 1, 2}，则两个集合的笛卡尔积为{(a, 0), (a, 1), (a, 2), (b, 0), (b, 1), (b, 2)}。
function cartesian(arr) {
if (arr.length < 2) return arr[0] || [];
return [].reduce.call(arr, function (col, set) {
let res = [];
col.forEach(c => {
set.forEach(s => {
let t = [].concat(Array.isArray(c) ? c : [c]);
t.push(s);
res.push(t);
})
});
return res;
});
}
function discarts() {
//笛卡尔积
var twodDscartes = function (a, b) {
var ret = [];
for (var i = 0; i < a.length; i++) {
for (var j = 0; j < b.length; j++) {
ret.push(ft(a[i], b[j]));
}
}
return ret;
}
var ft = function (a, b) {
if (!(a instanceof Array))
a = [a];
var ret = a.slice(0);
ret.push(b);
return ret;
}
//多个一起做笛卡尔积
return (function (data) {
var len = data.length;
if (len == 0)
return [];
else if (len == 1)
return data[0];
else {
var r = data[0];
for (var i = 1; i < len; i++) {
r = twodDscartes(r, data[i]);
}
return r;
}
})(arguments.length > 1 ? arguments : arguments[0]);
}
- 以上所述是给大家介绍的详解JS的递归函数，希望对大家有所帮助
