Question

On shell I tried on test db

post = {"title" : "My Blog Post", "content" : "Here's my blog post.", ... "date" : new Date()}

but when I tried to retrieve it using command

db.blog.find();

its giving me output

{ "_id" : ObjectId("4f13fdc4af1aaf90a686f8ae"), "title" : "My Blog Post", "content" : "Here's my blog post.", "date" : ISODate("2012-01-16T10:35:54.985Z") }

why its showing date as ISODate?? Can I not save date just what new Date() is return in js?

Answer 1

ISODate is the shell’s helper function to wrap javascript’s Date constructor. Calling ISODate() and new Date() should produce the exact same Date object, it will just be printed differently.

> var date = new Date(2012,01,16,10,35,54,985)
> var isodate = ISODate("2012-01-16T10:35:54.985Z")
> date.constructor == isodate.constructor
true

> date.constructor
function Date() {
    [native code]
}
> isodate.constructor
function Date() {
    [native code]
}

but:

> date.valueOf()
1329384954985
> isodate.valueOf()
1326710154985
> 

however if you use the exact same millisecond to construct them then they are equal:

> date = new Date(isodate.valueOf())
> print(date)
Mon Jan 16 2012 11:35:54 GMT+0100 (CET)
> date.valueOf() == isodate.valueOf()
true