JavaScript常见的工具函数

//禁止右键、选择复制

        ['contextmenu', 'selectstart', 'copy'].forEach(function (item) {
            document.addEventListener(item, function (e) {
                return e.returnValue = false
            })
        })

//禁止某些键盘事件

       document.addEventListener('keydown', function (e) {
           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)
       });

//性能分析，利用performance.timing进行性能分析

       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) +
                       '%')
               }
           })
       }

//检测数组中是否含有指定的值

        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;
        }

//填充array，从start位置开始，end位置结束，（不包含end位置），再返回原来数组

       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;
       }

//返回一个给定对象自身的所有可枚举属性值的数组

        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
        }

//返回一个由一个给定对象的自身可枚举属性组成的数组

        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
        }

//返回一个lower - upper之间的随机数

        function random(lower, upper) {
            lower = +lower || 0
            upper = +upper || 0
            return Math.random() * (upper - lower) + lower;
        }

//求取数组中非NaN数据中的最小值

        function min(arr) {
            arr = arr.filter(item => !_isNaN(item))
            return arr.length ? Math.min.apply(null, arr) : undefined
        }

//求取数组中非NaN数据中的最大值

       function max(arr) {
           arr = arr.filter(item => !_isNaN(item))
           return arr.length ? Math.max.apply(null, arr) : undefined
       }

//检查数据是否是非数字值

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

//window动画

        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);
            }

//退出全屏

       function exitFullscreen() {
           let elem = parent.document;
           elem.webkitCancelFullScreen ?
               elem.webkitCancelFullScreen() :
               elem.mozCancelFullScreen ?
               elem.mozCancelFullScreen() :
               elem.cancelFullScreen ?
               elem.cancelFullScreen() :
               elem.msExitFullscreen ?
               elem.msExitFullscreen() :
               elem.exitFullscreen ?
               elem.exitFullscreen() :
               alert("切换失败,可尝试Esc退出");
       }

//全屏

        function toFullScreen() {
            let elem = document.body;
            elem.webkitRequestFullScreen ?
                elem.webkitRequestFullScreen() :
                elem.mozRequestFullScreen ?
                elem.mozRequestFullScreen() :
                elem.msRequestFullscreen ?
                elem.msRequestFullscreen() :
                elem.requestFullScreen ?
                elem.requestFullScreen() :
                alert("浏览器不支持全屏");
        }

//base64数据导出文件，文件下载

       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);
           }
       }

//获取Url参数，返回一个对象

      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;
      }

//根据字符串路径获取对象属性 : ‘obj[0].count’

        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
            };
        };

//将指定字符串由一种时间格式转化为另一种 ，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
        }

//格式化时间

        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)
        }

//数组去重，返回一个新数组

        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
        }

//检测是否为PC端浏览器模式

       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)
       }

//获取浏览器信息

       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
           }
       }

//识别各种浏览器及平台

        //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;

//克隆数据，可深度克隆.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
        }

//对象属性复制，浅拷贝

        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);

//字符串首位大写

        function capitalize(str) {
            return str.charAt(0).toUpperCase() + str.slice(1)
        }
        // abc ==> Abc

//驼峰命名转横线命名：拆分字符串，使用 - 相连，并且转换为小写

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);

//横线转驼峰命名

        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)

//检查 value 是否为空.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 false;
        }

//检查 value 是否是类数组

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

//检查 value 是否为有效的类数组长度

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

//检查 value 是不是函数

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

//判断 value 是不是浏览器内置函数

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

//判断数据是不是时间对象

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

//判断数据是不是正则对象

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

//判断数据是不是数组类型的数据

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

//判断数据是不是Object类型的数据

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

//获取数据类型，返回结果为 Number、String、Object、Array等

        function getRawType(value) {
            return Object.prototype.toString.call(value).slice(8, -1)
        }

//isObjectLike：检查 value 是否是 类对象。 如果一个值是类对象，那么它不应该是 null，而且 typeof 后的结果是 “object”

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

//判断数据是不是引用类型的数据 (例如： arrays, functions, objects, regexes, new Number(0),以及 new String(’’))

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

//检测数据是不是原始数据

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

时间格式化

const formatTime = date => {
  const year = date.getFullYear()
  const month = date.getMonth() + 1
  const day = date.getDate()
  const hour = date.getHours()
  const minute = date.getMinutes()
  const second = date.getSeconds()

  return [hour, minute, second].map(formatNumber).join(':')
}

const formatNumber = n => {
  n = n.toString()
  return n[1] ? n : '0' + n
}

const getNowFormatDate = function(time) {
  if (!time) return '';
  let date = new Date(time);
  let Mouth = date.getMonth() < 9 ? '0' + (date.getMonth() + 1) : (date.getMonth() + 1);
  let Dates = date.getDate() < 10 ? '0' + date.getDate() : date.getDate();

  let Secon = date.getSeconds() < 10 ? "0" + date.getSeconds() : date.getSeconds()
  return date.getFullYear() + '-' + Mouth + '-' + Dates;
}
const getFullDate = function(time) {
  if (!time) return '';
  let date = new Date(time);
  let Mouth = date.getMonth() < 9 ? '0' + (date.getMonth() + 1) : (date.getMonth() + 1);
  let Dates = date.getDate() < 10 ? '0' + date.getDate() : date.getDate();
  let Hours = date.getHours() < 10 ? '0' + date.getHours() : date.getHours();
  let Min = date.getMinutes() < 10 ? '0' + date.getMinutes() : date.getMinutes()
  let Secon = date.getSeconds() < 10 ? "0" + date.getSeconds() : date.getSeconds()
  return date.getFullYear() + '-' + Mouth + '-' + Dates + " " + Hours + ":" + Min + ":" + Secon;
}

时间差

function timeFn(d1) {
  var dateBegin = new Date(d1.replace(/-/g, "/")); //将-转化为/，使用new Date
  var dateEnd = new Date(); //获取当前时间
  var dateDiff = dateEnd.getTime() - dateBegin.getTime(); //时间差的毫秒数
  var dayDiff = Math.floor(dateDiff / (24 * 3600 * 1000));
  var leave1 = dateDiff % (24 * 3600 * 1000)
  var hours = Math.floor(leave1 / (3600 * 1000));
  //计算相差分钟数
  var leave2 = leave1 % (3600 * 1000)
  var minutes = Math.floor(leave2 / (60 * 1000));
  //计算相差秒数
  var leave3 = leave2 % (60 * 1000)
  var seconds = Math.round(leave3 / 1000)
  var time;
  if (dayDiff > 0) {
    time = dayDiff + "天"
  } else if (hours > 0) {
    time = hours + "小时"
  } else if (minutes > 0) {
    time = minutes + "分钟"
  } else {
    time = seconds + "秒"
  }
  return time
}