js的时间格式化

在web开发中，常常会碰到时间转换成指定的字符串形式，如果是后台，没什么问题（有现成的系统方法，如C#：DateTime.ToString("yyyy-MM-dd")），但在前端得自己写一个转换的方法（我好像没有看到过现成的js包，不知道是不是自己知识面太窄了），近来整理一些东西，顺便把这个贴出来（仿后台的转换方式，但有种情况没有兼容：DateTime.ToString("yyyy-MMM-dd")，此时月份会转换成中文，我做的项目中没有用到转换成中文日期的情况，所以暂时没写；其次，目前支持json类型的时间和js内置的时间类型），各位勿喷

function DateToString(dateFormat, currentDate) {
    if (null == currentDate) {
        throw new Error("the value of date is required");
    }

    //json类型的时间
    var date_pattern = /^\/Date\(\d{13}\)\/$/;
    if (date_pattern.test(currentDate)) {
        currentDate = new Date(parseInt(currentDate.replace("/Date(", "").replace(")/", "")));
    }
    else if (!(currentDate instanceof Date)) {
        throw new Error("the data type is invalid");
    }

    var year = currentDate.getFullYear();
    var month = currentDate.getMonth() + 1;
    var day = currentDate.getDate();
    var hour = currentDate.getHours();
    var minute = currentDate.getMinutes();
    var second = currentDate.getSeconds();
    var millisecond = currentDate.getMilliseconds();

    var match_result;
    var json = [
        { "p": "y+", "v": year, "c": "y" },
        { "p": "M+", "v": month, "c": "M" },
        { "p": "d+", "v": day, "c": "d" },
        { "p": "h+", "v": hour > 12 ? hour - 12 : hour, "c": "h" },
        { "p": "H+", "v": hour, "c": "H" },
        { "p": "m+", "v": minute, "c": "m" },
        { "p": "s+", "v": second, "c": "s" },
        { "p": "f+", "v": millisecond, "c": "f" }
    ];

    var m = eval(json);
    for (var i = 0; i < m.length; i++) {
        var _reg = new RegExp(m[i].p, "g");

        while ((match_result = _reg.exec(dateFormat)) != null) {
            match_result = match_result[0];
            var value = m[i].v;

            switch (m[i].c) {
                case 'y':
                    if (match_result.length <= 2) {
                        dateFormat = dateFormat.replace(match_result, value.toString().substr(2, 2));
                    }
                    else {
                        dateFormat = dateFormat.replace(match_result, value);
                    }
                    break;
                case 'M':
                case 'd':
                case 'h':
                case 'H':
                case 'm':
                case 's':
                    if (match_result.length <= 1) {
                        dateFormat = dateFormat.replace(match_result, value);
                    }
                    else {
                        dateFormat = dateFormat.replace(match_result, value < 10 ? "0" + value : value);
                    }
                    break;
                case 'f':
                    switch (match_result.length) {
                        case 1:
                            dateFormat = dateFormat.replace(match_result, value.toString().substr(0, 1));
                            break;
                        case 2:
                            dateFormat = dateFormat.replace(match_result, value.toString().substr(0, 2));
                            break;
                        default:
                            dateFormat = dateFormat.replace(match_result, value);
                            break;
                    }
                    break;
            }
        }
    }
    return dateFormat;
}

调用方式：DateToString("yyyyy年MM月dd日", val);