JS开发常用工具函数

摘要：检测数据是不是除了外的原始数据检测数据是不是原始数据判断数据是不是引用类型的数据例如以及检查是否是类对象。返回一个布尔值，表示该值是否为的成员。

function isStatic(value) {
    return(
        typeof value === "string" ||
        typeof value === "number" ||
        typeof value === "boolean" ||
        typeof value === "undefined" ||
        value === null
    )
}

function isPrimitive(value) {
    return isStatic(value) || typeof value === "symbol"
}

function isObject(value) {
      let type = typeof value;
      return value != null && (type == "object" || type == "function");
}

function isObjectLike(value) {
      return value != null && typeof value == "object";
}

function getRawType(value) {
    return Object.prototype.toString.call(value).slice(8, -1)
}
//getoRawType([]) ==> Array

function isPlainObject(obj) {
    return Object.prototype.toString.call(obj) === "[object Object]"
}

function isArray(arr) {
    return Object.prototype.toString.call(arr) === "[object Array]"
}

将isArray挂载到Array上

Array.isArray = Array.isArray || isArray;

function isRegExp(value) {
    return Object.prototype.toString.call(value) === "[object RegExp]"
}

function isDate(value) {
    return Object.prototype.toString.call(value) === "[object Date]"
}

内置函数toString后的主体代码块为 [native code] ，而非内置函数则为相关代码，所以非内置函数可以进行拷贝(toString后掐头去尾再由Function转)

function isNative(value) {
    return typeof value === "function" && /native code/.test(value.toString())
}

function isFunction(value) {
    return Object.prototype.toString.call(value) === "[object Function]"
}

function isLength(value) {
      return typeof value == "number" && value > -1 && value % 1 == 0 && value <= Number.MAX_SAFE_INTEGER;
}

如果一个值被认为是类数组，那么它不是一个函数，并且value.length是个整数，大于等于 0，小于或等于 Number.MAX_SAFE_INTEGER。这里字符串也将被当作类数组

function isArrayLike(value) {
      return value != null && isLength(value.length) && !isFunction(value);
}

如果是null，直接返回true；如果是类数组，判断数据长度；如果是Object对象，判断是否具有属性；如果是其他数据，直接返回false(也可改为返回true)

function isEmpty(value) {
    if (value == null) {
        return true;
    }
    if (isArrayLike(value)) {
        return !value.length;
    }else if(isPlainObject(value)){
          for (let key in value) {
            if (hasOwnProperty.call(value, key)) {
              return false;
            }
        }
        return true;
    }
    return false;
}

function cached(fn) {
    let cache = Object.create(null);
    return function cachedFn(str) {
        let hit = cache[str];
        return hit || (cache[str] = fn(str))
    }
}

let camelizeRE = /-(w)/g;
function camelize(str) {
    return str.replace(camelizeRE, function(_, c) {
        return c ? c.toUpperCase() : "";
    })
}
//ab-cd-ef ==> abCdEf
//使用记忆函数
let _camelize = cached(camelize)

let hyphenateRE = /B([A-Z])/g;
function hyphenate(str){
    return str.replace(hyphenateRE, "-$1").toLowerCase()
}
//abCd ==> ab-cd
//使用记忆函数
let _hyphenate = cached(hyphenate);

function capitalize(str){
    return str.charAt(0).toUpperCase() + str.slice(1)
}
// abc ==> Abc
//使用记忆函数
let _capitalize = cached(capitalize)

function extend(to, _from) {
    for(let key in _from) {
        to[key] = _from[key];
    }
    return to
}

Object.assign = Object.assign || function(){
    if(arguments.length == 0) throw new TypeError("Cannot convert undefined or null to object");
    
    let target = arguments[0],
        args = Array.prototype.slice.call(arguments, 1),
        key
    args.forEach(function(item){
        for(key in item){
            item.hasOwnProperty(key) && ( target[key] = item[key] )
        }
    })
    return target
}

使用Object.assign可以浅克隆一个对象：

let clone = Object.assign({}, target)

简单的深克隆可以使用JSON.parse()和JSON.stringify()，这两个api是解析json数据的，所以只能解析除symbol外的原始类型及数组和对象

let clone = JSON.parse( JSON.stringify(target) )

这里列出了原始类型，时间、正则、错误、数组、对象的克隆规则，其他的可自行补充

function clone(value, deep){
    if(isPrimitive(value)){
        return value
    }
    
    if (isArrayLike(value)) { //是类数组
        value = Array.prototype.slice.call(value)
        return value.map(item => deep ? clone(item, deep) : item)
       }else if(isPlainObject(value)){ //是对象
           let target = {}, key;
          for (key in value) {
            value.hasOwnProperty(key) && ( target[key] = deep ? clone(value[key], deep) : value[key] )
        }
    }
    
    let type = getRawType(value)
    
    switch(type){
        case "Date":
        case "RegExp": 
        case "Error": value = new window[type](value); break;
    }
    return value
}

//运行环境是浏览器
let inBrowser = typeof window !== "undefined";
//运行环境是微信
let inWeex = typeof WXEnvironment !== "undefined" && !!WXEnvironment.platform;
let weexPlatform = inWeex && WXEnvironment.platform.toLowerCase();
//浏览器 UA 判断
let UA = inBrowser && window.navigator.userAgent.toLowerCase();
let isIE = UA && /msie|trident/.test(UA);
let isIE9 = UA && UA.indexOf("msie 9.0") > 0;
let isEdge = UA && UA.indexOf("edge/") > 0;
let isAndroid = (UA && UA.indexOf("android") > 0) || (weexPlatform === "android");
let isIOS = (UA && /iphone|ipad|ipod|ios/.test(UA)) || (weexPlatform === "ios");
let isChrome = UA && /chrome/d+/.test(UA) && !isEdge;

function getExplorerInfo() {
    let t = navigator.userAgent.toLowerCase();
    return 0 <= t.indexOf("msie") ? { //ie < 11
        type: "IE",
        version: Number(t.match(/msie ([d]+)/)[1])
    } : !!t.match(/trident/.+?rv:(([d.]+))/) ? { // ie 11
        type: "IE",
        version: 11
    } : 0 <= t.indexOf("edge") ? {
        type: "Edge",
        version: Number(t.match(/edge/([d]+)/)[1])
    } : 0 <= t.indexOf("firefox") ? {
        type: "Firefox",
        version: Number(t.match(/firefox/([d]+)/)[1])
    } : 0 <= t.indexOf("chrome") ? {
        type: "Chrome",
        version: Number(t.match(/chrome/([d]+)/)[1])
    } : 0 <= t.indexOf("opera") ? {
        type: "Opera",
        version: Number(t.match(/opera.([d]+)/)[1])
    } : 0 <= t.indexOf("Safari") ? {
        type: "Safari",
        version: Number(t.match(/version/([d]+)/)[1])
    } : {
        type: t,
        version: -1
    }
}

function isPCBroswer() {
    let e = navigator.userAgent.toLowerCase()
        , t = "ipad" == e.match(/ipad/i)
        , i = "iphone" == e.match(/iphone/i)
        , r = "midp" == e.match(/midp/i)
        , n = "rv:1.2.3.4" == e.match(/rv:1.2.3.4/i)
        , a = "ucweb" == e.match(/ucweb/i)
        , o = "android" == e.match(/android/i)
        , s = "windows ce" == e.match(/windows ce/i)
        , l = "windows mobile" == e.match(/windows mobile/i);
    return !(t || i || r || n || a || o || s || l)
}

function unique(arr){
    if(!isArrayLink(arr)){ //不是类数组对象
        return arr
    }
    let result = []
    let objarr = []
    let obj = Object.create(null)
    
    arr.forEach(item => {
        if(isStatic(item)){//是除了symbol外的原始数据
            let key = item + "_" + getRawType(item);
            if(!obj[key]){
                obj[key] = true
                result.push(item)
            }
        }else{//引用类型及symbol
            if(!objarr.includes(item)){
                objarr.push(item)
                result.push(item)
            }
        }
    })
    
    return resulte
}

window.Set = window.Set || (function () {
    function Set(arr) {
        this.items = arr ? unique(arr) : [];
        this.size = this.items.length; // Array的大小
    }
    Set.prototype = {
        add: function (value) {
            // 添加元素,若元素已存在,则跳过，返回 Set 结构本身。
            if (!this.has(value)) {
                this.items.push(value);
                this.size++;
            }
            return this;
        },
        clear: function () {
            //清除所有成员，没有返回值。
            this.items = []
            this.size = 0
        },
        delete: function (value) {
            //删除某个值，返回一个布尔值，表示删除是否成功。
            return this.items.some((v, i) => {
                if(v === value){
                    this.items.splice(i,1)
                    return true
                }
                return false
            })
        },
        has: function (value) {
            //返回一个布尔值，表示该值是否为Set的成员。
            return this.items.some(v => v === value)
        },
        values: function () {
            return this.items
        },
    }

    return Set;
}());

function repeat(str, n) {
    let res = "";
    while(n) {
        if(n % 2 === 1) {
            res += str;
        }
        if(n > 1) {
            str += str;
        }
        n >>= 1;
    }
    return res
};
//repeat("123",3) ==> 123123123

function dateFormater(formater, t){
    let date = t ? new Date(t) : new Date(),
        Y = date.getFullYear() + "",
        M = date.getMonth() + 1,
        D = date.getDate(),
        H = date.getHours(),
        m = date.getMinutes(),
        s = date.getSeconds();
    return formater.replace(/YYYY|yyyy/g,Y)
        .replace(/YY|yy/g,Y.substr(2,2))
        .replace(/MM/g,(M<10?"0":"") + M)
        .replace(/DD/g,(D<10?"0":"") + D)
        .replace(/HH|hh/g,(H<10?"0":"") + H)
        .replace(/mm/g,(m<10?"0":"") + m)
        .replace(/ss/g,(s<10?"0":"") + s)
}
// dateFormater("YYYY-MM-DD HH:mm", t) ==> 2019-06-26 18:30
// dateFormater("YYYYMMDDHHmm", t) ==> 201906261830

from的格式应对应str的位置

function dateStrForma(str, from, to){
    //"20190626" "YYYYMMDD" "YYYY年MM月DD日"
    str += ""
    let Y = ""
    if(~(Y = from.indexOf("YYYY"))){
        Y = str.substr(Y, 4)
        to = to.replace(/YYYY|yyyy/g,Y)
    }else if(~(Y = from.indexOf("YY"))){
        Y = str.substr(Y, 2)
        to = to.replace(/YY|yy/g,Y)
    }

    let k,i
    ["M","D","H","h","m","s"].forEach(s =>{
        i = from.indexOf(s+s)
        k = ~i ? str.substr(i, 2) : ""
        to = to.replace(s+s, k)
    })
    return to
}
// dateStrForma("20190626", "YYYYMMDD", "YYYY年MM月DD日") ==> 2019年06月26日
// dateStrForma("121220190626", "----YYYYMMDD", "YYYY年MM月DD日") ==> 2019年06月26日
// dateStrForma("2019年06月26日", "YYYY年MM月DD日", "YYYYMMDD") ==> 20190626

// 一般的也可以使用正则来实现
//"2019年06月26日".replace(/(d{4})年(d{2})月(d{2})日/, "$1-$2-$3") ==> 2019-06-26

function getPropByPath(obj, path, strict) {
      let tempObj = obj;
      path = path.replace(/[(w+)]/g, ".$1"); //将[0]转化为.0
      path = path.replace(/^./, ""); //去除开头的.

      let keyArr = path.split("."); //根据.切割
      let i = 0;
      for (let len = keyArr.length; i < len - 1; ++i) {
        if (!tempObj && !strict) break;
        let key = keyArr[i];
        if (key in tempObj) {
            tempObj = tempObj[key];
        } else {
            if (strict) {//开启严格模式，没找到对应key值，抛出错误
                throw new Error("please transfer a valid prop path to form item!");
            }
            break;
        }
      }
      return {
        o: tempObj, //原始数据
        k: keyArr[i], //key值
        v: tempObj ? tempObj[keyArr[i]] : null // key值对应的值
      };
};

function GetUrlParam(){
    let url = document.location.toString();
    let arrObj = url.split("?");
    let params = Object.create(null)
    if (arrObj.length > 1){
        arrObj = arrObj[1].split("&");
        arrObj.forEach(item=>{
            item = item.split("=");
            params[item[0]] = item[1]
        })
    }
    return params;
}
// ?a=1&b=2&c=3 ==> {a: "1", b: "2", c: "3"}

function downloadFile(filename, data){
    let DownloadLink = document.createElement("a");

    if ( DownloadLink ){
        document.body.appendChild(DownloadLink);
        DownloadLink.style = "display: none";
        DownloadLink.download = filename;
        DownloadLink.href = data;

        if ( document.createEvent ){
            let DownloadEvt = document.createEvent("MouseEvents");

            DownloadEvt.initEvent("click", true, false);
            DownloadLink.dispatchEvent(DownloadEvt);
        }
        else if ( document.createEventObject )
            DownloadLink.fireEvent("onclick");
        else if (typeof DownloadLink.onclick == "function" )
            DownloadLink.onclick();

        document.body.removeChild(DownloadLink);
    }
}

function toFullScreen(){
    let el = document.documentElement;
    let rfs = el.requestFullScreen || el.webkitRequestFullScreen || el.mozRequestFullScreen || el.msRequestFullScreen;

    //typeof rfs != "undefined" && rfs
    if (rfs) {
        rfs.call(el);
    }else if (typeof window.ActiveXObject !== "undefined") {
        //for IE，这里其实就是模拟了按下键盘的F11，使浏览器全屏
        let wscript = new ActiveXObject("WScript.Shell");
        if (wscript != null) {
            wscript.SendKeys("{F11}");
        }
    }else{
        alert("浏览器不支持全屏");
    }
}

function exitFullscreen(){
    let el = parent.document;
    let cfs = el.cancelFullScreen || el.webkitCancelFullScreen || el.mozCancelFullScreen || el.exitFullScreen;

    //typeof cfs != "undefined" && cfs
    if (cfs) {
        cfs.call(el);
    }else if (typeof window.ActiveXObject !== "undefined") {
        //for IE，这里和fullScreen相同，模拟按下F11键退出全屏
        let wscript = new ActiveXObject("WScript.Shell");
        if (wscript != null) {
            wscript.SendKeys("{F11}");
        }
    }else{
        alert("切换失败,可尝试Esc退出")
    }
}

window.requestAnimationFrame = window.requestAnimationFrame ||
    window.webkitRequestAnimationFrame ||
    window.mozRequestAnimationFrame ||
    window.msRequestAnimationFrame ||
    window.oRequestAnimationFrame ||
    function (callback) {
        //为了使setTimteout的尽可能的接近每秒60帧的效果
        window.setTimeout(callback, 1000 / 60);
    };
    
window.cancelAnimationFrame = window.cancelAnimationFrame ||
    Window.webkitCancelAnimationFrame ||
    window.mozCancelAnimationFrame ||
    window.msCancelAnimationFrame ||
    window.oCancelAnimationFrame ||
    function (id) {
        //为了使setTimteout的尽可能的接近每秒60帧的效果
        window.clearTimeout(id);
    }

原生的isNaN会把参数转换成数字(valueof)，而null、true、false以及长度小于等于1的数组(元素为非NaN数据)会被转换成数字，这不是我想要的。Symbol类型的数据不具有valueof接口，所以isNaN会抛出错误，这里放在后面，可避免错误

function _isNaN(v){
    return !(typeof v === "string" || typeof v === "number") || isNaN(v)
}

function max(arr){
    arr = arr.filter(item => !_isNaN(item))
    return arr.length ? Math.max.apply(null, arr) : undefined
}
//max([1, 2, "11", null, "fdf", []]) ==> 11

function min(arr){
    arr = arr.filter(item => !_isNaN(item))
    return arr.length ? Math.min.apply(null, arr) : undefined
}
//min([1, 2, "11", null, "fdf", []]) ==> 1

lower、upper无论正负与大小，但必须是非NaN的数据

function random(lower, upper){
    lower = +lower || 0
    upper = +upper || 0
    return Math.random() * (upper - lower) + lower;
}
//random(0, 0.5) ==> 0.3567039135734613
//random(2, 1) ===> 1.6718418553475423
//random(-2, -1) ==> -1.4474325452361945

Object.keys = Object.keys || function keys(object) {
    if(object === null || object === undefined){
        throw new TypeError("Cannot convert undefined or null to object");
    }
    let result = []
    if(isArrayLike(object) || isPlainObject(object)){
        for (let key in object) {
            object.hasOwnProperty(key) && ( result.push(key) )
        }
    }
    return result
}

Object.values = Object.values || function values(object) {
    if(object === null || object === undefined){
        throw new TypeError("Cannot convert undefined or null to object");
    }
    let result = []
    if(isArrayLike(object) || isPlainObject(object)){
        for (let key in object) {
            object.hasOwnProperty(key) && ( result.push(object[key]) )
        }
    }
    return result
}

Array.prototype.fill = Array.prototype.fill || function fill(value, start, end) {
    let ctx = this
    let length = ctx.length;
    
    start = parseInt(start)
    if(isNaN(start)){
        start = 0
    }else if (start < 0) {
        start = -start > length ? 0 : (length + start);
      }
      
      end = parseInt(end)
      if(isNaN(end) || end > length){
          end = length
      }else if (end < 0) {
        end += length;
    }
    
    while (start < end) {
        ctx[start++] = value;
    }
    return ctx;
}
//Array(3).fill(2) ===> [2, 2, 2]

Array.prototype.includes = Array.prototype.includes || function includes(value, start){
    let ctx = this
    let length = ctx.length;
    
    start = parseInt(start)
    if(isNaN(start)){
        start = 0
    }else if (start < 0) {
        start = -start > length ? 0 : (length + start);
      }
    
    let index = ctx.indexOf(value)
    
    return index >= start;
}

Array.prototype.find = Array.prototype.find || function find(fn, ctx){
    fn = fn.bind(ctx)
    
    let result;
    this.some((value, index, arr), thisValue) => {
        return fn(value, index, arr) ? (result = value, true) : false
    })
    
    return result
}

Array.prototype.findIndex = Array.prototype.findIndex || function findIndex(fn, ctx){
    fn = fn.bind(ctx)
    
    let result;
    this.some((value, index, arr), thisValue) => {
        return fn(value, index, arr) ? (result = index, true) : false
    })
    
    return result
}

window.onload = function(){
    setTimeout(function(){
        let t = performance.timing
        console.log("DNS查询耗时 ：" + (t.domainLookupEnd - t.domainLookupStart).toFixed(0))
        console.log("TCP链接耗时 ：" + (t.connectEnd - t.connectStart).toFixed(0))
        console.log("request请求耗时 ：" + (t.responseEnd - t.responseStart).toFixed(0))
        console.log("解析dom树耗时 ：" + (t.domComplete - t.domInteractive).toFixed(0))
        console.log("白屏时间 ：" + (t.responseStart - t.navigationStart).toFixed(0))
        console.log("domready时间 ：" + (t.domContentLoadedEventEnd - t.navigationStart).toFixed(0))
        console.log("onload时间 ：" + (t.loadEventEnd - t.navigationStart).toFixed(0))

        if(t = performance.memory){
            console.log("js内存使用占比 ：" + (t.usedJSHeapSize / t.totalJSHeapSize * 100).toFixed(2) + "%")
        }
    })
}

document.addEventListener("keydown", function(event){
    return !(
        112 == event.keyCode || //F1
        123 == event.keyCode || //F12
        event.ctrlKey && 82 == event.keyCode || //ctrl + R
        event.ctrlKey && 78 == event.keyCode || //ctrl + N
        event.shiftKey && 121 == event.keyCode || //shift + F10
        event.altKey && 115 == event.keyCode || //alt + F4
        "A" == event.srcElement.tagName && event.shiftKey //shift + 点击a标签
    ) || (event.returnValue = false)
});

["contextmenu", "selectstart", "copy"].forEach(function(ev){
    document.addEventListener(ev, function(event){
        return event.returnValue = false
    })
});

github地址：https://github.com/hfhan/tools