整理JS一些常用的工具函数

1.JS判断是否为空

/**
 * JS判断是否为空
 * @param val
 * @returns {boolean}
 */
function isNull(val) {
    if (val == undefined || val == null || val == "" || val == ''
        || val == "undefined" || val == "null" || val == "NULL") {
        return true;
    }
    return false;
}

2.JS时间戳转成时间

timeStamp2String(1526552438244); 	// 2018-05-17 18:20:38

/**
 * JS时间戳转成时间
 * @param time
 * @returns
 */
function timeStamp2String(time){
    var datetime = new Date();
    datetime.setTime(time);
    var year = datetime.getFullYear();
    var month = datetime.getMonth() + 1 < 10 ? "0" + (datetime.getMonth() + 1) : datetime.getMonth() + 1;
    var date = datetime.getDate() < 10 ? "0" + datetime.getDate() : datetime.getDate();
    var hour = datetime.getHours()< 10 ? "0" + datetime.getHours() : datetime.getHours();
    var minute = datetime.getMinutes()< 10 ? "0" + datetime.getMinutes() : datetime.getMinutes();
    var second = datetime.getSeconds()< 10 ? "0" + datetime.getSeconds() : datetime.getSeconds();
    return year + "-" + month + "-" + date+" "+hour+":"+minute+":"+second;
}

3.JS时间戳转成时间(通用版，可以自定义格式)

/**
 * JS时间戳转成时间
 * @param time
 * @returns
 */
function formatDate(timestamp, formats){
    formats = formats || 'Y-M-D';
	var myDate = undefined;
	if (timestamp) {
            if (typeof(timestamp) != 'string') {
		myDate = timestamp;
            } 
            else {
                myDate = new Date(timestamp);
            }
	} 
        else {
            myDate = new Date();
	}

	var year = myDate.getFullYear();
	var month = formatDigit(myDate.getMonth() + 1);
	var day = formatDigit(myDate.getDate());
	var hour = formatDigit(myDate.getHours());
	var minute = formatDigit(myDate.getMinutes());
	var second = formatDigit(myDate.getSeconds());
	return formats.replace(/Y|M|D|h|m|s/g, (matches) => {
		return {
			Y: year,
			M: month,
			D: day,
			h: hour,
			m: minute,
			s: second
		} [matches];
	});
}

4.JS生成指定位数的随机整数

/**
 * JS生成指定位数的随机整数
 * @param count
 * @returns {string}
 */
function getRandomNum(count){
    var arr = new Array;
    var reNum = "";
    for(var i=0;i<count;i++){
        arr[i] = parseInt(Math.random()*10);
        reNum += String(arr[i]);
    }
    return reNum;
}

5.去除空格

/**
 * JS生成指定位数的随机整数
 * @param str
 * @param type 1-所有空格 2-前后空格 3-前空格 4-后空格
 * @returns {string}
 */
function strTrim(str, type) {
    type = type || 2
    switch (type) {
        case 1:
            return str.replace(/\s+/g, "");
        case 2:
            return str.replace(/(^\s*)|(\s*$)/g, "");
        case 3:
            return str.replace(/(^\s*)/g, "");
        case 4:
            return str.replace(/(\s*$)/g, "");
        default:
            return str;
    }
}

6.JS格式化现在距${endTime}的剩余时间

/**
 * JS格式化现在距${endTime}的剩余时间
 * @param  {Date} endTime
 * @return {String}
 */
function formatRemainTime(endTime) {
    var startDate = new Date(); //开始时间
    var endDate = new Date(endTime); //结束时间
    var t = endDate.getTime() - startDate.getTime(); //时间差
    var d = 0,
        h = 0,
        m = 0,
        s = 0;
    if (t >= 0) {
        d = Math.floor(t / 1000 / 3600 / 24);
        h = Math.floor(t / 1000 / 60 / 60 % 24);
        m = Math.floor(t / 1000 / 60 % 60);
        s = Math.floor(t / 1000 % 60);
    }
    return d + "天 " + h + "小时 " + m + "分钟 " + s + "秒";
}

7.JS格式化${startTime}距现在的已过时间

/**
 * JS格式化${startTime}距现在的已过时间
 * @param  {Date} startTime
 * @return {String}
 */
function formatPassTime(startTime) {
    var currentTime = Date.parse(new Date()),
        time = currentTime - new Date(startTime),
        day = parseInt(time / (1000 * 60 * 60 * 24)),
        hour = parseInt(time / (1000 * 60 * 60)),
        min = parseInt(time / (1000 * 60)),
        month = parseInt(day / 30),
        year = parseInt(month / 12);
    if (year) return year + "年前";
    if (month) return month + "个月前";
    if (day) return day + "天前";
    if (hour) return hour + "小时前";
    if (min) return min + "分钟前";
    else return '刚刚';
}

8.JS Base64字符串编码与解码

base64Encode("test");    // dGVzdA==
base64Decode(test);     // test

/**
 * BASE64加密
 * @param str
 * @returns {string}
 */
function base64Encode(str) {
    return btoa(unescape(encodeURIComponent(str)));
}

/**
 * BASE64解密
 * @param str
 * @returns {string}
 */
function base64Decode(str) {
    return decodeURIComponent(escape(atob(str)));
}

9.JS检查输入的字符是否具有特殊字符

checkQuote("dasd1!/,/.");    // true
checkQuote("52014sdsda");    // false

/**
 * JS检查输入的字符是否具有特殊字符
 * @param str 字符串
 * @returns true 或 false; true表示包含特殊字符 主要用于注册信息的时候验证
 */
function checkQuote(str) {
    var items = new Array("~", "`", "!", "@", "#", "$", "%", "^", "&", "*", "{", "}", "[", "]", "(", ")");
    items.push(":", ";", "'", "|", "\", "<", ">", "?", "/", "<<", ">>", "||", "//");
    items.push("select", "delete", "update", "insert", "create", "drop", "alter", "trancate");
    str = str.toLowerCase();
    for ( var i = 0; i < items.length; i++) {
        if (str.indexOf(items[i]) >= 0) {
            return true;
        }
    }
    return false;
}

10.JS将手机号格式化，中间部分以 * 号代替

phoneToStar("16666666666");  // 166****6666

/**
 * JS将手机号格式化，中间部分以 * 号代替
 * @param phone
 * @returns {string | * | void}
 */
function phoneToStar( phone ) {
    return phone.replace(/(\d{3})\d{4}(\d{4})/, "$1****$2");
}

11.JS获取地址栏参数的值

// 若当前的URL地址为：a.html?t1=1&t2=2&t3=3
console.log(getUrlParam("t1"));	// 1

/**
 * JS获取地址栏参数的值
 * @param name 对应的参数
 * @returns {*} 如果有，则返回参数值，没有则返回null
 */
function getUrlParam(name){
    var reg = new RegExp("(^|&)" + name + "=([^&]*)(&|$)");
    var r = window.location.search.substr(1).match(reg);
    if (r != null) {
        return unescape(r[2]);
    } else {
        return null;
    }
}

12.JS时间个性化输出功能

//可用于列表展示的时间显示
console.log(timeFormat(new Date()));	// 例：刚刚

/**
 * JS时间个性化输出功能
 * 1、< 60s, 显示为“刚刚”
 * 2、>= 1min && < 60 min, 显示与当前时间差“XX分钟前”
 * 3、>= 60min && < 1day, 显示与当前时间差“今天 XX:XX”
 * 4、>= 1day && < 1year, 显示日期“XX月XX日 XX:XX”
 * 5、>= 1year, 显示具体日期“XXXX年XX月XX日 XX:XX”
 * @param time
 * @returns {string}
 */
function timeFormat(time){
    var date = new Date(time),
        curDate = new Date(),
        year = date.getFullYear(),
        month = date.getMonth() + 10,
        day = date.getDate(),
        hour = date.getHours(),
        minute = date.getMinutes(),
        curYear = curDate.getFullYear(),
        curHour = curDate.getHours(),
        timeStr;

    if(year < curYear){
        timeStr = year +'年'+ month +'月'+ day +'日 '+ hour +':'+ minute;
    }else{
        var pastTime = curDate - date,
            pastH = pastTime/3600000;

        if(pastH > curHour){
            timeStr = month +'月'+ day +'日 '+ hour +':'+ minute;
        }else if(pastH >= 1){
            timeStr = '今天 ' + hour +':'+ minute +'分';
        }else{
            var pastM = curDate.getMinutes() - minute;
            if(pastM > 1){
                timeStr = pastM +'分钟前';
            }else{
                timeStr = '刚刚';
            }
        }
    }
    return timeStr;
}

13.JS生成UUID

generateUUID();	// 例如：7ceb31a7-41b9-45ed-915b-14c7ad0fddf6

/**
 * generateUUID 生成UUID
 * @returns {string} 返回字符串
 */
function generateUUID(){
    var d = new Date().getTime();
    var uuid = 'xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx'.replace(/[xy]/g, function(c) {
        var r = (d + Math.random()*16)%16 | 0;
        d = Math.floor(d/16);
        return (c=='x' ? r : (r&0x7|0x8)).toString(16);
    });
    return uuid;
}

14.函数去抖

//调用
let n = 1;
function func () {
    n += 1;
    console.log('n', n);
}
window.onresize = debance(func, 1000);

function debance(fn, delay) {
    let t = null;
    return function() {
        let that = this;
        let args = arguments;
        clearTimeout(t);
        t = setTimeout(function() {
            fn.apply(context, args);
        }, delay);
    }
}

15.函数节流

//调用
let n = 1;
function func () {
    n += 1;
    console.log('n', n);
}
window.onresize = throttle(func, 1000);

function throttle (fn, delay) {
    let preTime = Date.now();
    return function() {
        let that = this;
        let args = arguments;
        let nowTime = Date.now();
        if (preTime + delay < nowTime) {
            fn.apply(that, args);
            preTime = nowTime;
        }
    }
}