JS 常用方法汇总(不定期更新)

/**
 * 获取当前日期
 * @returns {string}
 */
Common.currentDate = function () {
  // 获取当前日期
  var date = new Date();

  // 获取当前月份
  var nowMonth = date.getMonth() + 1;

  // 获取当前是几号
  var strDate = date.getDate();

  // 添加分隔符“-”
  var seperator = "-";

  // 对月份进行处理，1-9月在前面添加一个“0”
  if (nowMonth >= 1 && nowMonth <= 9) {
    nowMonth = "0" + nowMonth;
  }

  // 对日期进行处理，1-9号在前面添加一个“0”
  if (strDate >= 0 && strDate <= 9) {
    strDate = "0" + strDate;
  }

  // 最后拼接字符串，得到一个格式为(yyyy-MM-dd)的日期
  return date.getFullYear() + seperator + nowMonth + seperator + strDate;
};

/**
 * 获取url上的参数(支持中文)
 * @param key
 * @returns {any}
 */
Common.getUrlParam = function (key) {
  // 获取参数
  var url = window.location.search;
  // 正则筛选地址栏
  var reg = new RegExp("(^|&)" + key + "=([^&]*)(&|$)");
  // 匹配目标参数
  var result = url.substr(1).match(reg);
  //返回参数值
  return result ? decodeURIComponent(result[2]) : null;
}

/**
 * 数字千分位格式化
 * @param number 要格式化的数字
 * @param decimals 保留几位小数
 * @param dec_point 小数点符号
 * @param thousands_sep 千分位符号
 * @returns {string}
 */
Common.numberFormat = function (number, decimals, dec_point, thousands_sep) {
  number = (number + '').replace(/[^0-9+-Ee.]/g, '');
  var n = !isFinite(+number) ? 0 : +number,
    prec = !isFinite(+decimals) ? 2 : Math.abs(decimals),
    sep = (typeof thousands_sep === 'undefined') ? ',' : thousands_sep,
    dec = (typeof dec_point === 'undefined') ? '.' : dec_point,
    s = '',
    toFixedFix = function (n, prec) {
      var k = Math.pow(10, prec);
      return '' + Math.ceil(n * k) / k;
    };

  s = (prec ? toFixedFix(n, prec) : '' + Math.round(n)).split('.');
  var re = /(-?\d+)(\d{3})/;
  while (re.test(s[0])) {
    s[0] = s[0].replace(re, "$1" + sep + "$2");
  }

  if ((s[1] || '').length < prec) {
    s[1] = s[1] || '';
    s[1] += new Array(prec - s[1].length + 1).join('0');
  }
  return s.join(dec);
};

/**
 * 千分位格式化数字转为普通数字
 * @param formatedNum
 * @returns {number}
 */
Common.rNumberFormat = function (formatedNum) {
  return parseFloat(formatedNum.replace(/[^\d\.-]/g, ""));
};

/**
 * 构造树型结构数据
 * @param {*} data 数据源
 * @param {*} id id字段 默认 'id'
 * @param {*} parentId 父节点字段 默认 'parentId'
 * @param {*} children 孩子节点字段 默认 'children'
 * @param {*} rootId 根Id 默认 0
 */
Common.treeBuilder =  function(data, id, parentId, children, rootId) {
  id = id || 'id'
  parentId = parentId || 'parentId'
  children = children || 'children'
  rootId = rootId || 0
  //对源数据深度克隆
  const cloneData = JSON.parse(JSON.stringify(data))
  //循环所有项
  const treeData = cloneData.filter(father => {
    let branchArr = cloneData.filter(child => {
      //返回每一项的子级数组
      return father[id] === child[parentId]
    });
    branchArr.length > 0 ? father[children] = branchArr : '';
    //返回第一层
    return father[parentId] === rootId;
  });
  return treeData != '' ? treeData : data;
};

/**
 * 重新封装jQuery的 ajax方法
 **/
var $ax = function (url, success, error) {
  this.url = url;
  this.type = "post";
  this.data = {};
  this.dataType = "json";
  this.async = false;
  this.success = success;
  this.error = error;
};

$ax.prototype = {
  start: function () {
    var me = this;
    var result = "";

    if (this.url.indexOf("?") === -1) {
      this.url = this.url + "?jstime=" + new Date().getTime();
    } else {
      this.url = this.url + "&jstime=" + new Date().getTime();
    }

    $.ajax({
      type: me.type,
      url: me.url,
      dataType: me.dataType,
      async: me.async,
      data: me.data,
      beforeSend: function (data) {

      },
      success: function (data) {
        result = data;
        if (me.success !== undefined) {
          me.success(data);
        }
      },
      error: function (data) {
        if (me.error !== undefined) {
          me.error(data);
        }
      }
    });

    return result;
  },

  set: function (key, value) {
    if (typeof key === "object") {
      for (var i in key) {
        if (typeof i === "function")
          continue;
        this.data[i] = key[i];
      }
    } else {
      this.data[key] = (typeof value === "undefined") ? $("#" + key).val() : value;
    }
    return this;
  },

  setData: function (data) {
    this.data = data;
    return this;
  },

  clear: function () {
    this.data = {};
    return this;
  }
};