How to reference a key from the same object when creating it?

Question

Say I have an object such as this:

var time = {
    \'second\': 1000,
    \'minute\': 1000 * 60,
    \'hour\'  : 1000 * 60 * 60,
    \'day\'   : 1000 * 60 *          


        

Answer 1

You can't do this as the object does not exist yet while it's parsed.

The only way to avoid this is creating an object and then adding the keys one by one - so you already have an object which has the properties you want to re-use.

Answer 2

you can't reference properties from itself if you are declaring it like that as the properties dont yet exist, you might want to try a different approach

var time = {};
time.second = 1000;
time.minute = time.second * 60;
...

Answer 3

You can use the getters syntax supported by most modern browser :

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

Answer 4

Change the object to a constructor function and you can do this:

function Time() {
    this.second = 1000;
    this.minute = this.second * 60;
    this.hour = this.minute * 60;
    this.day = this.hour * 24;
    this.week = this.day * 7;
}

// Use
var time = new Time();

Answer 5

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

Even shorter:

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
    };
})();

And finally the minified version of this:

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}}()