JS 常用方法封装

关于JS的一些总结, 持续更新中……

注：以下是一些常用方法封装，以备不时之需，当然 也可以直接使用 lodash，moment，dayjs 等等这种现成的包实现

1、输入一个值，返回其数据类型

function type(para) {
  return Object.prototype.toString.call(para);
}

2、数组去重

function unique1(arr) {
  return [...new Set(arr)];
}

function unique2(arr) {
  let obj = {};
  return arr.filter((ele) => {
    if (!obj[ele]) {
      obj[ele] = true;
      return true;
    }
  });
}

function unique3(arr) {
  let result = [];
  arr.forEach((ele) => {
    if (result.indexOf(ele) == -1) {
      result.push(ele);
    }
  });
  return result;
}

3、字符串去重

String.prototype.unique = function () {
  let obj = {},
    str = "",
    len = this.length;
  for (let i = 0; i < len; i++) {
    if (!obj[this[i]]) {
      str += this[i];
      obj[this[i]] = true;
    }
  }
  return str;
};

//去除连续的字符串
function uniq(str) {
  return str.replace(/(\w)\1+/g, "$1");
}

4、深拷贝 浅拷贝

//深克隆（深克隆不考虑函数）
function deepClone(obj, result) {
  let result = result || {};
  for (let prop in obj) {
    if (obj.hasOwnProperty(prop)) {
      if (typeof obj[prop] == "object" && obj[prop] !== null) {
        // 引用值(obj/array)且不为null
        if (Object.prototype.toString.call(obj[prop]) == "[object Object]") {
          // 对象
          result[prop] = {};
        } else {
          // 数组
          result[prop] = [];
        }
        deepClone(obj[prop], result[prop]);
      } else {
        // 原始值或func
        result[prop] = obj[prop];
      }
    }
  }
  return result;
}

// 深浅克隆是针对引用值
function deepClone(target) {
  if (typeof target !== "object") {
    return target;
  }
  let result;
  if (Object.prototype.toString.call(target) == "[object Array]") {
    // 数组
    result = [];
  } else {
    // 对象
    result = {};
  }
  for (let prop in target) {
    if (target.hasOwnProperty(prop)) {
      result[prop] = deepClone(target[prop]);
    }
  }
  return result;
}
// 无法复制函数
let o1 = jsON.parse(jsON.stringify(obj1));

5、reverse 底层原理和扩展

// 改变原数组
Array.prototype.myReverse = function () {
  let len = this.length;
  for (let i = 0; i < len; i++) {
    let temp = this[i];
    this[i] = this[len - 1 - i];
    this[len - 1 - i] = temp;
  }
  return this;
};

6、圣杯模式的继承

function inherit(Target, Origin) {
  function F() {}
  F.prototype = Origin.prototype;
  Target.prototype = new F();
  Target.prototype.constructor = Target;
  // 最终的原型指向
  Target.prop.uber = Origin.prototype;
}

7、找出字符串中第一次只出现一次的字母

String.prototype.firstAppear = function () {
  let obj = {},
    len = this.length;
  for (let i = 0; i < len; i++) {
    if (obj[this[i]]) {
      obj[this[i]]++;
    } else {
      obj[this[i]] = 1;
    }
  }
  for (let prop in obj) {
    if (obj[prop] == 1) {
      return prop;
    }
  }
};

8、找元素的第 n 级父元素

function parents(ele, n) {
  while (ele && n) {
    ele = ele.parentElement ? ele.parentElement : ele.parentNode;
    n--;
  }
  return ele;
}

9、 返回元素的第 n 个兄弟节点

function retSibling(e, n) {
  while (e && n) {
    if (n > 0) {
      if (e.nextElementSibling) {
        e = e.nextElementSibling;
      } else {
        for (e = e.nextSibling; e && e.nodeType !== 1; e = e.nextSibling);
      }
      n--;
    } else {
      if (e.previousElementSibling) {
        e = e.previousElementSibling;
      } else {
        for (
          e = e.previousElementSibling;
          e && e.nodeType !== 1;
          e = e.previousElementSibling
        );
      }
      n++;
    }
  }
  return e;
}

10、封装 mychildren，解决浏览器的兼容问题

function myChildren(e) {
  let children = e.childNodes,
    arr = [],
    len = children.length;
  for (let i = 0; i < len; i++) {
    if (children[i].nodeType === 1) {
      arr.push(children[i]);
    }
  }
  return arr;
}

11、判断元素有没有子元素

function hasChildren(e) {
  let children = e.childNodes,
    len = children.length;
  for (let i = 0; i < len; i++) {
    if (children[i].nodeType === 1) {
      return true;
    }
  }
  return false;
}

12、我一个元素插入到另一个元素的后面

Element.prototype.insertAfter = function (target, elen) {
  let nextElen = elen.nextElenmentSibling;
  if (nextElen == null) {
    this.appendChild(target);
  } else {
    this.insertBefore(target, nextElen);
  }
};

13、返回当前的时间（年月日时分秒）

function 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"
  );
}

14、获得滚动条的滚动距离

function getScrollOffset() {
  if (window.pageXOffset) {
    return {
      x: window.pageXOffset,
      y: window.pageYOffset,
    };
  } else {
    return {
      x: document.body.scrollLeft + document.documentElement.scrollLeft,
      y: document.body.scrollTop + document.documentElement.scrollTop,
    };
  }
}

15、获得视口的尺寸

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,
      };
    }
  }
}

16、获取任一元素的任意属性

function getStyle(elem, prop) {
  return window.getComputedStyle
    ? window.getComputedStyle(elem, null)[prop]
    : elem.currentStyle[prop];
}

17、绑定事件的兼容代码

function addEvent(elem, type, handle) {
  if (elem.addEventListener) {
    //非ie和非ie9
    elem.addEventListener(type, handle, false);
  } else if (elem.attachEvent) {
    //ie6到ie8
    elem.attachEvent("on" + type, function () {
      handle.call(elem);
    });
  } else {
    elem["on" + type] = handle;
  }
}

18、解绑事件

function removeEvent(elem, type, handle) {
  if (elem.removeEventListener) {
    //非ie和非ie9
    elem.removeEventListener(type, handle, false);
  } else if (elem.detachEvent) {
    //ie6到ie8
    elem.detachEvent("on" + type, handle);
  } else {
    elem["on" + type] = null;
  }
}

19、取消冒泡的兼容代码

function stopBubble(e) {
  if (e && e.stopPropagation) {
    e.stopPropagation();
  } else {
    window.event.cancelBubble = true;
  }
}

20、检验字符串是否是回文

function isPalina(str) {
  if (Object.prototype.toString.call(str) !== "[object String]") {
    return false;
  }
  let len = str.length;
  for (let i = 0; i < len / 2; i++) {
    if (str[i] != str[len - 1 - i]) {
      return false;
    }
  }
  return true;
}

21、检验字符串是否是回文

function isPalindrome(str) {
  str = str.replace(/\W/g, "").toLowerCase();
  console.log(str);
  return str == str.split("").reverse().join("");
}

22、兼容 getElementsByClassName 方法

Element.prototype.getElementsByClassName =
  Document.prototype.getElementsByClassName = function (_className) {
    let allDomArray = document.getElementsByTagName("*");
    let lastDomArray = [];
    function trimSpace(strClass) {
      let reg = /\s+/g;
      return strClass.replace(reg, " ").trim();
    }
    for (let i = 0; i < allDomArray.length; i++) {
      let classArray = trimSpace(allDomArray[i].className).split(" ");
      for (let j = 0; j < classArray.length; j++) {
        if (classArray[j] == _className) {
          lastDomArray.push(allDomArray[i]);
          break;
        }
      }
    }
    return lastDomArray;
  };

23、运动函数

function animate(obj, json, callback) {
  clearInterval(obj.timer);
  let speed, current;
  obj.timer = setInterval(function () {
    let lock = true;
    for (let prop in json) {
      if (prop == "opacity") {
        current = parseFloat(window.getComputedStyle(obj, null)[prop]) * 100;
      } else {
        current = parseInt(window.getComputedStyle(obj, null)[prop]);
      }
      speed = (json[prop] - current) / 7;
      speed = speed > 0 ? Math.ceil(speed) : Math.floor(speed);

      if (prop == "opacity") {
        obj.style[prop] = (current + speed) / 100;
      } else {
        obj.style[prop] = current + speed + "px";
      }
      if (current != json[prop]) {
        lock = false;
      }
    }
    if (lock) {
      clearInterval(obj.timer);
      typeof callback == "function" ? callback() : "";
    }
  }, 30);
}

24、弹性运动

function ElasticMovement(obj, target) {
  clearInterval(obj.timer);
  let iSpeed = 40,
    a,
    u = 0.8;
  obj.timer = setInterval(function () {
    a = (target - obj.offsetLeft) / 8;
    iSpeed = iSpeed + a;
    iSpeed = iSpeed * u;
    if (Math.abs(iSpeed) <= 1 && Math.abs(a) <= 1) {
      console.log("over");
      clearInterval(obj.timer);
      obj.style.left = target + "px";
    } else {
      obj.style.left = obj.offsetLeft + iSpeed + "px";
    }
  }, 30);
}

25、封装自己的 forEach 方法

Array.prototype.myForEach = function (func, obj) {
  let len = this.length;
  let _this = arguments[1] ? arguments[1] : window;
  // let _this=arguments[1]||window;
  for (let i = 0; i < len; i++) {
    func.call(_this, this[i], i, this);
  }
};

26、封装自己的 filter 方法

Array.prototype.myFilter = function (func, obj) {
  let len = this.length;
  let arr = [];
  let _this = arguments[1] || window;
  for (let i = 0; i < len; i++) {
    func.call(_this, this[i], i, this) && arr.push(this[i]);
  }
  return arr;
};

27、数组 map 方法

Array.prototype.myMap = function (func) {
  let arr = [];
  let len = this.length;
  let _this = arguments[1] || window;
  for (let i = 0; i < len; i++) {
    arr.push(func.call(_this, this[i], i, this));
  }
  return arr;
};

28、数组 every 方法

Array.prototype.myEvery = function (func) {
  let flag = true;
  let len = this.length;
  let _this = arguments[1] || window;
  for (let i = 0; i < len; i++) {
    if (func.apply(_this, [this[i], i, this]) == false) {
      flag = false;
      break;
    }
  }
  return flag;
};

29、数组 reduce 方法

Array.prototype.myReduce = function (func, initialValue) {
  let len = this.length,
    nextValue,
    i;
  if (!initialValue) {
    // 没有传第二个参数
    nextValue = this[0];
    i = 1;
  } else {
    // 传了第二个参数
    nextValue = initialValue;
    i = 0;
  }
  for (; i < len; i++) {
    nextValue = func(nextValue, this[i], i, this);
  }
  return nextValue;
};

30、获取 url 中的参数

function getWindonHref() {
  let sHref = window.location.href;
  let args = sHref.split("?");
  if (args[0] === sHref) {
    return "";
  }
  let hrefarr = args[1].split("#")[0].split("&");
  let obj = {};
  for (let i = 0; i < hrefarr.length; i++) {
    hrefarr[i] = hrefarr[i].split("=");
    obj[hrefarr[i][0]] = hrefarr[i][1];
  }
  return obj;
}

31、数组排序

// 快排 [left] + min + [right]
function quickArr(arr) {
  if (arr.length <= 1) {
    return arr;
  }
  let left = [],
    right = [];
  let pIndex = Math.floor(arr.length / 2);
  let p = arr.splice(pIndex, 1)[0];
  for (let i = 0; i < arr.length; i++) {
    if (arr[i] <= p) {
      left.push(arr[i]);
    } else {
      right.push(arr[i]);
    }
  }
  // 递归
  return quickArr(left).concat([p], quickArr(right));
}

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

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

32、遍历 Dom 树

// 给定页面上的DOM元素,将访问元素本身及其所有后代(不仅仅是它的直接子元素)
// 对于每个访问的元素，函数讲元素传递给提供的回调函数
function traverse(element, callback) {
  callback(element);
  let list = element.children;
  for (let i = 0; i < list.length; i++) {
    traverse(list[i], callback);
  }
}

33、原生 js 封装 ajax

function ajax(method, url, callback, data, flag) {
  let xhr;
  flag = flag || true;
  method = method.toUpperCase();
  if (window.XMLHttpRequest) {
    xhr = new XMLHttpRequest();
  } else {
    xhr = new ActiveXObject("Microsoft.XMLHttp");
  }
  xhr.onreadystatechange = function () {
    if (xhr.readyState == 4 && xhr.status == 200) {
      console.log(2);
      callback(xhr.responseText);
    }
  };

  if (method == "GET") {
    let date = new Date(),
      timer = date.getTime();
    xhr.open("GET", url + "?" + data + "&timer" + timer, flag);
    xhr.send();
  } else if (method == "POST") {
    xhr.open("POST", url, flag);
    xhr.setRequestHeader("Content-Type", "application/x-www-form-urlencoded");
    xhr.send(data);
  }
}

34、异步加载 script

function loadScript(url, callback) {
  let oscript = document.createElement("script");
  if (oscript.readyState) {
    // ie8及以下版本
    oscript.onreadystatechange = function () {
      if (
        oscript.readyState === "complete" ||
        oscript.readyState === "loaded"
      ) {
        callback();
      }
    };
  } else {
    oscript.onload = function () {
      callback();
    };
  }
  oscript.src = url;
  document.body.appendChild(oscript);
}

35、cookie 管理

let cookie = {
  set: function (name, value, time) {
    document.cookie = name + "=" + value + "; max-age=" + time;
    return this;
  },
  remove: function (name) {
    return this.setCookie(name, "", -1);
  },
  get: function (name, callback) {
    let allCookieArr = document.cookie.split("; ");
    for (let i = 0; i < allCookieArr.length; i++) {
      let itemCookieArr = allCookieArr[i].split("=");
      if (itemCookieArr[0] === name) {
        return itemCookieArr[1];
      }
    }
    return undefined;
  },
};

36、实现 bind()方法

Function.prototype.myBind = function (target) {
  let target = target || window;
  let _args1 = [].slice.call(arguments, 1);
  let self = this;
  let temp = function () {};
  let F = function () {
    let _args2 = [].slice.call(arguments, 0);
    let parasArr = _args1.concat(_args2);
    return self.apply(this instanceof temp ? this : target, parasArr);
  };
  temp.prototype = self.prototype;
  F.prototype = new temp();
  return F;
};

// 或者
Function.prototype.myBind = function (context) {
  // 判断调用对象是否为函数
  if (typeof this !== "function") {
    throw new Error("Type error");
  }
  // 获取参数
  const args = [...arguments].slice(1),
  const fn = this;
  return function Fn() {
    return fn.apply(
      this instanceof Fn ? this : context,
      // 当前的这个 arguments 是指 Fn 的参数
      args.concat(...arguments)
    );
  };
};

37、实现 call()方法

Function.prototype.myCall = function (context) {
  // 判断调用对象
  if (typeof this !== "function") {
    throw new Error("Type error");
  }
  // 首先获取参数
  let args = [...arguments].slice(1);
  let result = null;
  // 判断 context 是否传入，如果没有传就设置为 window
  context = context || window;
  // 将被调用的方法设置为 context 的属性
  // this 即为我们要调用的方法
  context.fn = this;
  // 执行要被调用的方法
  result = context.fn(...args);
  // 删除手动增加的属性方法
  delete context.fn;
  // 将执行结果返回
  return result;
};

38、实现 apply()方法

// Function.prototype.myApply = function () {
//   let ctx = arguments[0] || window;
//   ctx.fn = this;
//   if (!arguments[1]) {
//     let result = ctx.fn();
//     delete ctx.fn;
//     return result;
//   }
//   let result = ctx.fn(...arguments[1]);
//   delete ctx.fn;
//   return result;
// };

Function.prototype.myApply = function (context) {
  if (typeof this !== "function") {
    throw new Error("Type error");
  }
  let result = null;
  context = context || window;
  // 与上面代码相比，这里使用 Symbol 来保证属性唯一
  // 也就是保证不会重写用户自己原来定义在 context 中的同名属性
  const fnSymbol = Symbol();
  context[fnSymbol] = this;
  // 执行要被调用的方法
  if (arguments[1]) {
    result = context[fnSymbol](...arguments[1]);
  } else {
    result = context[fnSymbol]();
  }
  delete context[fnSymbol];
  return result;
};

39、防抖

function debounce(handle, delay) {
  let timer = null;
  return function () {
    let _self = this,
      _args = arguments;
    clearTimeout(timer);
    timer = setTimeout(function () {
      handle.apply(_self, _args);
    }, delay);
  };
}

40、节流

function throttle(handler, wait) {
  let lastTime = 0;
  return function (e) {
    let nowTime = new Date().getTime();
    if (nowTime - lastTime > wait) {
      handler.apply(this, arguments);
      lastTime = nowTime;
    }
  };
}

41、requestAnimFrame 兼容性方法

window.requestAnimFrame = (function () {
  return (
    window.requestAnimationFrame ||
    window.webkitRequestAnimationFrame ||
    window.mozRequestAnimationFrame ||
    function (callback) {
      window.setTimeout(callback, 1000 / 60);
    }
  );
})();

42、cancelAnimFrame 兼容性方法

window.cancelAnimFrame = (function () {
  return (
    window.cancelAnimationFrame ||
    window.webkitCancelAnimationFrame ||
    window.mozCancelAnimationFrame ||
    function (id) {
      window.clearTimeout(id);
    }
  );
})();

43、jsonp 底层方法

function jsonp(url, callback) {
  let oscript = document.createElement("script");
  if (oscript.readyState) {
    // ie8及以下版本
    oscript.onreadystatechange = function () {
      if (
        oscript.readyState === "complete" ||
        oscript.readyState === "loaded"
      ) {
        callback();
      }
    };
  } else {
    oscript.onload = function () {
      callback();
    };
  }
  oscript.src = url;
  document.body.appendChild(oscript);
}

44、获取 url 上的参数

function getUrlParam(sUrl, sKey) {
  let result = {};
  sUrl.replace(/(\w+)=(\w+)(?=[&|#])/g, function (ele, key, val) {
    if (!result[key]) {
      result[key] = val;
    } else {
      let temp = result[key];
      result[key] = [].concat(temp, val);
    }
  });
  if (!sKey) {
    return result;
  } else {
    return result[sKey] || "";
  }
}

45、格式化时间

function formatDate(t, str) {
  let obj = {
    yyyy: t.getFullYear(),
    yy: ("" + t.getFullYear()).slice(-2),
    M: t.getMonth() + 1,
    MM: ("0" + (t.getMonth() + 1)).slice(-2),
    d: t.getDate(),
    dd: ("0" + t.getDate()).slice(-2),
    H: t.getHours(),
    HH: ("0" + t.getHours()).slice(-2),
    h: t.getHours() % 12,
    hh: ("0" + (t.getHours() % 12)).slice(-2),
    m: t.getMinutes(),
    mm: ("0" + t.getMinutes()).slice(-2),
    s: t.getSeconds(),
    ss: ("0" + t.getSeconds()).slice(-2),
    w: ["日", "一", "二", "三", "四", "五", "六"][t.getDay()],
  };
  return str.replace(/([a-z]+)/gi, function ($1) {
    return obj[$1];
  });
}

46、验证邮箱的正则表达式

function isAvailableEmail(sEmail) {
  let reg = /^([\w+\.])+@\w+([.]\w+)+$/;
  return reg.test(sEmail);
}

47、函数柯里化

//是把接受多个参数的函数变换成接受一个单一参数(最初函数的第一个参数)的函数，并且返回接受余下的参数且返回结果的新函数的技术

function curryIt(fn) {
  let length = fn.length,
    args = [];
  let result = function (arg) {
    args.push(arg);
    length--;
    if (length <= 0) {
      return fn.apply(this, args);
    } else {
      return result;
    }
  };
  return result;
}

48、大数相加

function sumBigNumber(a, b) {
  let res = "", //结果
    temp = 0; //按位加的结果及进位
  a = a.split("");
  b = b.split("");
  while (a.length || b.length || temp) {
    //~~按位非 1.类型转换，转换成数字 2.~~undefined==0
    temp += ~~a.pop() + ~~b.pop();
    res = (temp % 10) + res;
    temp = temp > 9;
  }
  return res.replace(/^0+/, "");
}

49、单例模式

function getSingle(func) {
  let result;
  return function () {
    if (!result) {
      result = new func(arguments);
    }
    return result;
  };
}

50、从 RGB 转换为 HEX

const rgbToHex = (r, g, b) => {
  const toHex = (num) => {
    // 转换为16进制
    const hex = num.toString(16);

    return hex.length === 1 ? `0${hex}` : hex;
  };

  return `#${toHex(r)}${toHex(g)}${toHex(b)}`;
  return;
};

console.log(rgbToHex(46, 32, 67)); // #2e2043

51、判断两个字符串是否为互相排列

const isAnagram = (str1, str2) => {
  const normalize = (str) =>
    str.toLowerCase().normalize("NFD").split("").sort().join("");
  return normalize(str1) === normalize(str2);
};

console.log(isAnagram("anagram", "naagram")); // true
console.log(isAnagram("car", "rat")); // false
console.log(isAnagram("heArt", "traEH")); // true

52、判断两个字符串是否为相反回文字符串

const isReverse = (str1, str2) => {
  const normalize = (str) =>
    str.toLowerCase().normalize("NFD").split("").reverse().join("");
  return normalize(str1) === str2;
};

console.log(isReverse("anagram", "naagram")); // false
console.log(isReverse("tar", "rat")); // true

53、手写 promise.all

function promiseAll(promises) {
  return new Promise((resolve, reject) => {
    if(promises && !Array.isArray(promises)) {
      throw new TypeError("args must be a array!");
    }

    let count = 0;
    let length = promises.length;
    let results = [];

    if(!length) return resolve([])

    for(let i = 0;i < length;i++) {
      Promise.resolve(promises[i]).then((val) => {
        count++;
        results.push(val);
        if(count == length) {
          return resolve(results);
        }
      }, err => {
        return reject(err);
      })
    }
  })
}

54、Symbol 迭代器

• 创建一个迭代器，for...of...遍历

const LPL = {
  name: "TES",
  players: ["JackeyLove", "Karsa", "knight"],
  [Symbol.iterator]() {
    let index = 0;
    return {
      next: () => {
        if (index < this.players.length) {
          const res = { value: this.players[index], done: false };
          index++;
          return res;
        } else {
          return { value: undefined, done: true };
        }
      },
    };
  },
};
for (let item of LPL) {  //JackeyLove 
  console.log(item);     //Karsa 
}                        //knight

55、实现new

function myNew(context) { 
  // 设置新的对象
  let obj = new Object();
  // 指定_proto_ 为构造函数 prototype
  obj.__proto__ = context.prototype;
  // 重新指向this
  // [...arguments].slice(1) 去除第一个参数的其他剩余参数 通过apply 重新指向新的对象
  const result = context.apply(obj, [...arguments].slice(1));

  return typeof context === "object" ? res : obj;
}