Date confusion

[espruino-discuss]

Posted at 2016-08-03 by MichaelPralow

i am working with dates and got some confusing behaviour

>console.log(new Date(getTime()).toString());
Sun Jan 18 1970 00:24:12 GMT+0000
>console.log(new Date().toString());
Wed Aug 3 2016 19:29:50 GMT+0000

i expected to be able to create a new Date with the value from getTime()
getTime() returns a floating point number, but with rounding Math.round(getTime()); the result does not change

Is there some error in my code or my expectations, maybe some misinterpretation of the docs on my side?

[espruino-discuss]

Posted at 2016-08-04 by @allObjects

nope.... (no problem in your code) - may be... (in interpretation of doc)...

getTime() is an Espruino built in function... and shows ~ new Date().getTime() / 1000.

On power on - py Pico shows 949363215.70712661743 seconds for getTime() (Loading 2527 bytes from flash... is form reset() and save()).

>
Connected
>Loading 2620 bytes from flash...
>new Date().toString()
="Tue Feb 1 2000 00:00:18 GMT+0000"
>getTime()
=949363232.21488475799
> 

... after uploading, it shows more 'now': 1470274624.28208160400

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|   __|___ ___ ___ _ _|_|___ ___
|   __|_ -| . |  _| | | |   | . |
|_____|___|  _|_| |___|_|_|_|___|
          |_| http://espruino.com
 1v86 Copyright 2016 G.Williams
>echo(0);
=undefined
>new Date().toString()
="Thu Aug 4 2016 01:42:42 GMT+0000"
>getTime()
=1470274974.15566730499
>

Initially, there was no synchronization between time of your Browser/Web IDE and time of Espruino. Today, when uploading code (even empty editor pane), time is set to GMT+0000 (UTC) from the Browser/Web IDE has. Date() 'class'/object has always GMT+0000 / UTC. If Espruino connected to, for example, Web / http or a GPS, you may pull time from there.

You can set the time by taking the [ms] since "Thu, 01 Jan 1970 00:00:00 GMT" - in Browser Inspector Console with new Datae().getTime() - and divide them by 1000 to get seconds and feed those into setTime(seconds) in Espruino console. This will set your Espruino time to now in GMT+0000 / UTC.

This conversation 'fools' around with date and time formatting.