项目中常用的js方法封装---自留

1.输入一个值,返回其数据类型

type = para => {
  return Object.prototype.toString.call(para).slice(8,-1)  
}

2.冒泡排序

升序 bubbleAsSort()

bubbleAsSort = arr => {
  for (let i = 0; i < arr.length - 1; i++) {
    for (let j = 0; j < arr.length - 1 - i; j++) {
      if (arr[j] > arr[j + 1]) { let temp = arr[j + 1]; arr[j + 1] = arr[j]; arr[j] = temp; } } } return arr; }

降序 bubbleDeSort()

bubbleDeSort = arr => {
  for (let i = 0; i < arr.length - 1; i++) {
    for (let j = 0; j < arr.length - 1 - i; j++) {
      if (arr[j] < arr[j + 1]) { let temp = arr[j + 1]; arr[j + 1] = arr[j]; arr[j] = temp; } } } return arr; }

3.选择排序

升序 selectAsSort()

selectAsSort = arr => {
  let minIndex, temp;
  for (let i = 0; i < arr.length - 1; i++) {
    minIndex = i;
    for (let j = i + 1; j < arr.length; j++) { if (arr[j] < arr[minIndex]) { minIndex = j; } } temp = arr[i]; arr[i] = arr[minIndex]; arr[minIndex] = temp; } return arr; }

降序 selectDeSort()

selectDeSort = arr => {
  let minIndex, temp;
  for (let i = 0; i < arr.length - 1; i++) {
    minIndex = i;
    for (let j = i + 1; j < arr.length; j++) { if (arr[j] > arr[minIndex]) { minIndex = j; } } temp = arr[i]; arr[i] = arr[minIndex]; arr[minIndex] = temp; } return arr; }

4.插入排序

升序 insertAsSort()

insertAsSort = arr => {
  let current, preIndex;
  for (let i = 1; i < arr.length; i++) {
    current = arr[i];
    preIndex = i - 1;
    while (preIndex >= 0 && arr[preIndex] > current) {
      arr[preIndex + 1] = arr[preIndex];
      preIndex--;
    }
    arr[preIndex + 1] = current;
  }
  return arr; }

降序 insertDeSort()

insertDeSort = arr => {
  let current, preIndex;
  for (let i = 1; i < arr.length; i++) {
    current = arr[i];
    preIndex = i - 1;
    while (preIndex >= 0 && arr[preIndex] < current) {
      arr[preIndex + 1] = arr[preIndex];
      preIndex--;
    }
    arr[preIndex + 1] = current;
  }
  return arr; }

5.阶乘

factorial = num => {
  let count = 1;
  for (let i = 1; i <= num; i++) {
    count *= i;
  }
  return count;
}

6.两个数之间累乘

multBetride = (x, y) => {
  let count;
  if (x < y) {
    count = x;
    for (let i = x + 1; i <= y; i++) {
      count *= i;
    }
    return count; } else { count = y; for (let i = y + 1; i <= x; i++) { count *= i; } return count; } }

7.累加

（）里面可以放N个实参

function cumsum() {
    let sum = 0;
    for (let i = 0; i < arguments.length; i++) { sum += arguments[i]; } return sum; }

8.计时器(计算代码块(函数)执行时间)

无参 computeTime(f)

computeTime = code => {
  let startTime = new Date().getTime();
  code();
  let endTime = new Date().getTime();
  let time = endTime - startTime;
  return time;
}

有参 computeTime(f)
使用方法:computeTime(f,参数1,参数2......)

computeTime = f => {
  let startTime = new Date().getTime();
  let p = [];
  for (let i = 1; i < arguments.length; i++) {
    p.push(arguments[i])
  }
  f.apply(null, p)
  let endTime = new Date().getTime(); let Time = endTime - startTime; return Time; }

9.数组去重

arrDemp = arr => {
  let newArr = [];
  let m = {};
  for (let i = 0; i < arr.length; i++) {
    let n = arr[i]; if (m[n]) { } else { newArr.push(arr[i]); m[n] = true; } } return newArr; } let arr = [1,2,3,5,4,5,4,3,6] console.log(arrDemp(arr)); // [ 1, 2, 3, 5, 4, 6 ]

也可以使用ES6中的new Set，一步到位（注意兼容）

let arr = [1,2,3,5,4,5,4,3,6]
let arrDemp = new Set(arr)  //arrDemp是一个对象
let newArr = [...arrDemp]   //把arrDemp转化成数组
console.log(newArr);

10.统计数组中各个元素出现的次数

staArrNum = arr => {
  let obj = {};
  for (let i = 0; i < arr.length; i++) {
    let m = arr[i];
    if (obj.hasOwnProperty(m)) { obj[m] += 1; } else { obj[m] = 1; } } return obj; } let arr = [1, 2, 3, 6, 5, 3, 2, 1, 2, 3, 2, 1] console.log(staArrNum(arr)); // { '1': 3, '2': 4, '3': 3, '5': 1, '6': 1 }

11.在数组中找指定的元素,返回下标

arrFinNum = function (arr,num) {
  let index = -1;
  for (let i = 0; i < arr.length; i++) { if (num == arr[i]) { index = i; break; } } return index; } let arr = [1,2,3,4,5,6] console.log(arrFinNum(arr,4)); // 3

12.删除数组中的元素

delArrNum = (arr,val) => {
  let index = arrFinNum(arr, val) //调用了前面自行添加的arrFinNum方法
  if (index != -1) {
    return arr.splice(index, 1); } }

示例

let arr = [1, 2, 3, 4, 5, 6]

arrFinNum = (arr, num) => {
  let index = -1;
  for (let i = 0; i < arr.length; i++) { if (num == arr[i]) { index = i; break; } } return index; } delArrNum = (arr,val) => { let index = arrFinNum(arr, val) //调用了前面自行添加的arrFinNum方法 if (index != -1) { return arr.splice(index, 1); } } console.log(delArrNum(arr,2)); // [ 2 ]

13.时间戳转化成YMD格式

let date = Date.parse(new Date()) //  获取当前时间戳(毫秒)

dateFormat = (timestamp, formats) => {
  // formats格式包括
  // 1. Y-m-d
  // 2. Y-m-d H:i:s
  // 3. Y年m月d日
  // 4. Y年m月d日 H时i分
  formats = formats || 'Y-m-d';
  let zero = function (value) { if (value < 10) { return '0' + value; } return value; }; let myDate = timestamp ? new Date(timestamp) : new Date(); let year = myDate.getFullYear(); let month = zero(myDate.getMonth() + 1); let day = zero(myDate.getDate()); let hour = zero(myDate.getHours()); let minite = zero(myDate.getMinutes()); let second = zero(myDate.getSeconds()); return formats.replace(/Y|m|d|H|i|s/ig, function (matches) { return ({ Y: year, m: month, d: day, H: hour, i: minite, s: second })[matches]; }); }; console.log(dateFormat(date,'Y-m-d'));

14.数字超过9显示省略号

num_filter = val =>{
  val = val?val-0:0;
  if (val > 9 ) {
    return "…"
  }else{
    return val; } }

15.数字超过99显示99+

ninenum_filter = val =>{
  val = val?val-0:0;
  if (val > 99 ) {
    return "99+"
  }else{
    return val; } }

16.年

let date = Date.parse(new Date()) //  获取当前时间戳(毫秒)

dateY = time =>{
  let newDate = new Date(time);
  let {y}={y:newDate.getFullYear()};
  return `${y}`; } console.log(dateY(date));

17.年月

let date = Date.parse(new Date()) //  获取当前时间戳(毫秒)

dateYM = time => {
  let newDate = new Date(time);
  let { y, m, d } = { y: newDate.getFullYear(), m: newDate.getMonth() + 1, d: newDate.getDate() };
  return `${y}-${m}`; } console.log(dateYM(date));

19.年月日

可根据自己需求，自己添加或删除相应的时间

let date = Date.parse(new Date()) //  获取当前时间戳(毫秒)

dateymd = time => {
  let newDate = new Date(time);
  let { y, m, d } = { y: newDate.getFullYear(), m: newDate.getMonth() + 1, d: newDate.getDate() };
  return `${y}-${m}-${d}`; } console.log(dateymd2(date));

20.年月日时分秒

let date = Date.parse(new Date()) //  获取当前时间戳(毫秒)

dateTime = time => {
  let newDate = new Date(time);
  let { y, M, d, h, m, s } = { y: newDate.getFullYear(), M: newDate.getMonth() + 1, d: newDate.getDate(), h: newDate.getHours(), m: newDate.getMinutes(), s: newDate.getSeconds() };
  return `${y}-${M}-${d} ${h}:${m}:${s}`; } console.log(dateTime(date));

21.银行卡号分割

bank_filter = val =>{
  val += '';
  val = val.replace(/(\s)/g,'').replace(/(\d{4})/g,'$1 ').replace(/\s*$/,'');
  return val; }

22.计算时间N之前

time_filter = time => {
  time -= 0;
  let difTime = new Date().getTime() - time;
  let { h, m } = { h: parseInt(difTime / (3600 * 1000)), m: parseInt(difTime / (60 * 1000)) };
  let msg = "";
  if (h < 1) { msg = `${m}分钟前`; } else if (h >= 1 && h <= 24) { msg = `${h}小时前`; } else if (h > 24) { h = parseInt(h / 24) msg = `${h}天前`; } return msg; } //输入一个时间戳，能计算出来是多长时间之前 console.log(time_filter(68464646464)); //17445天前

23.二分查找

//非递归实现
binarySearch = (arr, key) => {
  let high = arr.length - 1,
    low = 0;
  while (low <= high) {
    let m = Math.floor((high + low) / 2);
    if (arr[m] == key) {
      return m; } if (key > arr[m]) { low = m + 1; } else { high = m - 1; } } return false; } let arr = [-1, 1, 3, 4, 5, 8, 32, 234, 12, 42]; console.log(binarySearch(arr, 4)); 复制代码

//递归实现
binarySearch = (arr, low, high, key) => {
  if (low > high) {
    return -1;
  }
  let mid = parseInt((high + low) / 2);
  if (arr[mid] == key) {
    return mid; } else if (arr[mid] > key) { high = mid - 1; return binarySearch(arr, low, high, key); } else if (arr[mid] < key) { low = mid + 1; return binarySearch(arr, low, high, key); } }; let arr = [-1, 1, 3, 4, 5, 8, 32, 234, 12, 42]; console.log(binarySearch(arr, 0, 13, 5));

24.获取上周本周下周时间

getDate = n => {
  let now = new Date();
  let year = now.getFullYear();
  let month = now.getMonth() + 1;
  let date = now.getDate();
  let day = now.getDay(); if (day !== 0) { n = n + (day - 1); } else { n = n + day; } if (day) { if (month > 1) { month = month; } else { year = year - 1; month = 12; } } now.setDate(now.getDate() - n); year = now.getFullYear(); month = now.getMonth() + 1; date = now.getDate(); let s = year + "-" + (month < 10 ? "0" + month : month) + "-" + (date < 10 ? "0" + date : date); return s; } /***参数都是以周一为基准的***/ //上周的开始时间 // console.log(getDate(7)); //上周的结束时间 // console.log(getDate(1)); //本周的开始时间 // console.log(getDate(0)); //本周的结束时间 // console.log(getDate(-6)); //下周的开始时间 // console.log(getDate(-7)); //下周结束时间 // console.log(getDate(-13));

25.获取当前时间(年月日)

getNowDate = () => {
  let nowdate = new Date();
  let y = nowdate.getFullYear();
  let m = nowdate.getMonth() + 1;
  let d = nowdate.getDate();
  return y + "-" + m + "-" + d; }

26.当前的时间(年月日时分秒)

getDateTime = () => {
  let date = new Date();
  year = date.getFullYear();
  month = date.getMonth() + 1;
  day = date.getDate();
  hour = date.getHours() + 1;
  minute = date.getMinutes();
  second = date.getSeconds();
  month = checkTime(month);
  day = checkTime(day);
  hour = checkTime(hour);
  minute = checkTime(minute);
  second = checkTime(second);
  function checkTime(i) {
    if (i < 10) {
      i = "0" + i;
    }
    return i; } return "" + year + "年" + month + "月" + day + "日" + hour + "时" + minute + "分" + second + "秒" } console.log(getDateTime());

27.防抖与节流

/**
 * 函数防抖 (只执行最后一次点击)
 */
Debounce = (fn, t) => {
    let delay = t || 500;
    let timer;
    return function () { let args = arguments; if(timer){ clearTimeout(timer); } timer = setTimeout(() => { timer = null; fn.apply(this, args); }, delay); } }; /* * 函数节流 */ Throttle = (fn, t) => { let last; let timer; let interval = t || 500; return function () { let args = arguments; let now = +new Date(); if (last && now - last < interval) { clearTimeout(timer); timer = setTimeout(() => { last = now; fn.apply(this, args); }, interval); } else { last = now; fn.apply(this, args); } } };

028.深拷贝

deepClone = source => {
  const targetObj = source.constructor === Array ? [] : {}; // 判断复制的目标是数组还是对象
  for (let keys in source) { // 遍历目标 if (source.hasOwnProperty(keys)) { if (source[keys] && typeof source[keys] === 'object') { // 如果值是对象，就递归一下 targetObj[keys] = source[keys].constructor === Array ? [] : {}; targetObj[keys] = deepClone(source[keys]); } else { // 如果不是，就直接赋值 targetObj[keys] = source[keys]; } } } return targetObj; } let str1 = { arr: [1, 2, 3], obj: { key: 'value' }, fn: function () { return 1; } }; let str3 = deepClone(str1); console.log(str3 === str1); // false console.log(str3.obj === str1.obj); // false console.log(str3.fn === str1.fn); // true

29.获取视口尺寸

需要在HTML文件中运行

function getViewportOffset() {
    if (window.innerWidth) {
        return { w: window.innerWidth, h: window.innerHeight } } else { // ie8及其以下 if (document.compatMode === "BackCompat") { // 怪异模式 return { w: document.body.clientWidth, h: document.body.clientHeight } } else { // 标准模式 return { w: document.documentElement.clientWidth, h: document.documentElement.clientHeight } } } }

30.倒计时(开始结束,自定义时间)

以下代码写到HTML的body中

<span id="clock">00:01:00:00</span>
<input id="start" type="button" value="开始" onclick="run()"> <input id="end" type="button" value="结束" onclick="stop()"> <script language="Javascript"> var normalelapse = 100; var nextelapse = normalelapse; var counter; var startTime; var start = clock.innerText; var finish = "00:00:00:00"; var timer = null; // 开始运行 function run() { start.disabled = true; end.disabled = false; counter = 0; // 初始化开始时间 startTime = new Date().valueOf(); // nextelapse是定时时间, 初始时为100毫秒 // 注意setInterval函数: 时间逝去nextelapse(毫秒)后, onTimer才开始执行 timer = window.setInterval("onTimer()", nextelapse); } // 停止运行 function stop() { start.disabled = false; end.disabled = true; window.clearTimeout(timer); } window.onload = function () { end.disabled = true; }; // 倒计时函数 function onTimer() { if (start == finish) { window.clearInterval(timer); alert("时间到了!"); return; } var hms = new String(start).split(":"); var ms = new Number(hms[3]); var s = new Number(hms[2]); var m = new Number(hms[1]); var h = new Number(hms[0]); ms -= 10; if (ms < 0) { ms = 90; s -= 1; if (s < 0) { s = 59; m -= 1; } if (m < 0) { m = 59; h -= 1; } } var ms = ms < 10 ? ("0" + ms) : ms; var ss = s < 10 ? ("0" + s) : s; var sm = m < 10 ? ("0" + m) : m; var sh = h < 10 ? ("0" + h) : h; start = sh + ":" + sm + ":" + ss + ":" + ms; clock.innerText = start; // 清除上一次的定时器 window.clearInterval(timer); // 自校验系统时间得到时间差, 并由此得到下次所启动的新定时器的时间nextelapse counter++; var counterSecs = counter * 100; var elapseSecs = new Date().valueOf() - startTime; var diffSecs = counterSecs - elapseSecs; nextelapse = normalelapse + diffSecs; if (nextelapse < 0) nextelapse = 0; // 启动新的定时器 timer = window.setInterval("onTimer()", nextelapse); } </script>

31.计时器(无开始结束)