JavaScript 常用代码集合

JavaScript 常用的扩展函数和方法

字符串相关扩展

• 字符串格式化

  String.prototype.format = function () {
      var args = arguments;
      return this.replace(/{(\d+)}/g, function (s, i) {
          return args[i];
      });
  };

日期相关处理扩展

• 日期格式化字符串扩展

  /**
   * 日期格式化
   * 例: new Date().format('yyyy-MM-dd hh:mm:ss.s') => "2017-08-24 16:15:40.693"
   * @param fmt 格式化字符串
   * @returns {*}
   */
  Date.prototype.format = function (fmt) { //author: meizz
      var o = {
          "M+": this.getMonth() + 1, //月份
          "d+": this.getDate(), //日
          "h+": this.getHours(), //小时
          "m+": this.getMinutes(), //分
          "s+": this.getSeconds(), //秒
          "q+": Math.floor((this.getMonth() + 3) / 3), //季度
          "S": this.getMilliseconds() //毫秒
      };
      if (/(y+)/.test(fmt)) fmt = fmt.replace(RegExp.$1, (this.getFullYear() + "")  .substr(4 - RegExp.$1.length));
      for (var k in o) {
          if (new RegExp("(" + k + ")").test(fmt)) {
              fmt = fmt.replace(RegExp.$1, (RegExp.$1.length === 1) ? o[k] : (("00"   + o[k]).substr(("" + o[k]).length)));
          }
      }
      return fmt;
  };

• 计算两个日期之间的差值

  /**
  * 获得时间差
  * @param time 时间
  * @param type 类型
  * @returns {Number} 差值
  */
  Date.prototype.diff = function (time, type) {
      //作为除数的数字
      var divNum = 1;
      switch (type.toLowerCase()) {
          case "second":
              divNum = 1000;
              break;
          case "minute":
              divNum = 1000 * 60;
              break;
          case "hour":
              divNum = 1000 * 3600;
              break;
          case "day":
              divNum = 1000 * 3600 * 24;
              break;
          default:
              break;
      }
      return parseInt((this.getTime() - time.getTime()) / parseInt(divNum));
  };
  /**
  * 获得相差秒数
  * @param time 时间
  * @returns {Number}
  */
  Date.prototype.diffSecond = function (time) {
      return this.diff(time, 'Second')
  };
  /**
  * 获得相差分钟
  * @param time 时间
  * @returns {Number}
  */
  Date.prototype.diffMinute = function (time) {
      return this.diff(time, 'Minute')
  };
  /**
  *
  * 获得相差小时
  * @param time 时间
  * @returns {Number}
  */
  Date.prototype.diffHour = function (time) {
      return this.diff(time, 'Hour')
  };
  /**
  * 获得相差日期
  * @param time 时间
  * @returns {Number}
  */
  Date.prototype.diffDay = function (time) {
      return this.diff(time, 'Day')
  };

比较两个对象之间的差异

var deepDiffMapper = function () {
    return {
        VALUE_CREATED: 'created',
        VALUE_UPDATED: 'updated',
        VALUE_DELETED: 'deleted',
        VALUE_UNCHANGED: 'unchanged',
        map: function (obj1, obj2) {
            if (this.isFunction(obj1) || this.isFunction(obj2)) {
                throw 'Invalid argument. Function given, object expected.';
            }
            if (this.isValue(obj1) || this.isValue(obj2)) {
                return {
                    type: this.compareValues(obj1, obj2),
                    data: (obj1 === undefined) ? obj2 : obj1
                };
            }

            var diff = {};
            for (var key in obj1) {
                if (this.isFunction(obj1[key])) {
                    continue;
                }

                var value2 = undefined;
                if ('undefined' != typeof (obj2[key])) {
                    value2 = obj2[key];
                }

                diff[key] = this.map(obj1[key], value2);
            }
            for (var key in obj2) {
                if (this.isFunction(obj2[key]) || ('undefined' != typeof (diff[key]))) {
                    continue;
                }

                diff[key] = this.map(undefined, obj2[key]);
            }

            return diff;

        },
        compareValues: function (value1, value2) {
            if (value1 === value2) {
                return this.VALUE_UNCHANGED;
            }
            if (this.isDate(value1) && this.isDate(value2) && value1.getTime() === value2.getTime()) {
                return this.VALUE_UNCHANGED;
            }
            if ('undefined' == typeof (value1)) {
                return this.VALUE_CREATED;
            }
            if ('undefined' == typeof (value2)) {
                return this.VALUE_DELETED;
            }

            return this.VALUE_UPDATED;
        },
        isFunction: function (obj) {
            return {}.toString.apply(obj) === '[object Function]';
        },
        isArray: function (obj) {
            return {}.toString.apply(obj) === '[object Array]';
        },
        isDate: function (obj) {
            return {}.toString.apply(obj) === '[object Date]';
        },
        isObject: function (obj) {
            return {}.toString.apply(obj) === '[object Object]';
        },
        isValue: function (obj) {
            return !this.isObject(obj) && !this.isArray(obj);
        }
    }
}();

var result = deepDiffMapper.map({
    a: 'i am unchanged',
    b: 'i am deleted',
    e: {
        a: 1,
        b: false,
        c: null
    },
    f: [1, {
        a: 'same',
        b: [{
            a: 'same'
        }, {
            d: 'delete'
        }]
    }],
    g: new Date('2017.11.25')
}, {
    a: 'i am unchanged',
    c: 'i am created',
    e: {
        a: '1',
        b: '',
        d: 'created'
    },
    f: [{
        a: 'same',
        b: [{
            a: 'same'
        }, {
            c: 'create'
        }]
    }, 1],
    g: new Date('2017.11.25')
});
console.log(result);