When I try this new Date('2015-01-25T17:00:00.000Z') it will returning the next date Jan 26 2015 00:00:00, this is an expected behaviour for me, but why it is like this?
Is there any explanation from this js behaviour when using TZ with value of OO:OO:OO.
The Z at the very end means "Zulu Time" which is another word for UTC.
The result you see in your console is the time in your current timezone. You are probably 5 hours ahead of UTC.
If you remove the Z, the output you get is the same as what you put in, because Javascript will use local time by default.
UTC (Zulu) time is '2015-01-25T17:00:00.000Z'. The local time in Jakarta is UTC+7: Jan 26 2015 00:00:00.
See Time in Indonesia and ISO 8601.