如何在创建时从同一对象引用键？ [英] How to reference a key from the same object when creating it?

问题描述

说我有这样一个对象：

var time = {
    'second': 1000,
    'minute': 1000 * 60,
    'hour'  : 1000 * 60 * 60,
    'day'   : 1000 * 60 * 60 * 24,
    'week'  : 1000 * 60 * 60 * 24 * 7
};

我如何缩短它以便引用其他键？

How would I shorten it so it would reference the other keys?

我的意思是这样的：

var time = {
    'second': 1000,
    'minute': this.second * 60,
    'hour'  : this.minute * 60,
    'day'   : this.hour   * 24,
    'week'  : this.day    * 7
}

我无法使用<$ c引用每个$ c> time.foo 因为该变量尚未初始化。我可以简单地在新命令上添加每个命令，例如 time ['hour'] = time.minute * 60; ，但我宁愿在一个命令中执行此操作。

I can't reference each using time.foo because the variable isn't initialized yet. I could simply add each on a new command, such as time['hour'] = time.minute * 60;, but I'd rather do it in one command.

推荐答案

var time = (function(){
    var second = 1000,
        minute = second * 60,
        hour = minute * 60,
        day = hour * 24,
        week = day * 7;
    return {
        'second': second,
        'minute': minute,
        'hour'  : hour,
        'day'   : day,
        'week'  : week
    };
})();

UPD

更短：

var time = (function(){
    var w, d, h, m, s;
    w = (d = (h = (m = (s = 1000) * 60) * 60) * 24) * 7;
    return {
        second: s,
        minute: m,
        hour  : h,
        day   : d,
        week  : w
    };
})();

最后是缩小版本：

var time=function(){var a,b,c,d,e;a=(b=(c=(d=(e=1e3)*60)*60)*24)*7;return{second:e,minute:d,hour:c,day:b,week:a}}()

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