array length

[espruino-discuss]

Posted at 2018-03-08 by 7oo1er

Hello

As I read in Internets, array.length can cut array to size. I need this to save only 100 last readings. But using lenght can, I think, cause some memory issues.
code:

a = new Array();
a = [1, 2, 3, 4, 5, 6];
console.log(a);

console requests:

>[ 1, 2, 3, 4, 5, 6 ]
=undefined
>a.length
=6
>a
=[ 1, 2, 3, 4, 5, 6 ]
>a.length = 2
=2
>a
=[ 1, 2, 3, 4, 5, 6, "length": 2 ]
> 

I can get a real array size only before trying to cut it.

[gfwilliams]

Posted at 2018-03-08 by @gfwilliams

I'm afraid Espruino doesn't support setting the array length - however it's trivial to work around.

You can use either of:

• Array.slice : http://www.espruino.com/Reference#l_Array_slice
• Array.splice : http://www.espruino.com/Reference#l_Array_splice
• Array.pop : http://www.espruino.com/Reference#l_Array_pop
• Array.shift : http://www.espruino.com/Reference#l_Array_shift

Also, if you're after storing a whole lot of readings, maybe look at using Uint8Array/etc as they'll be vastly more efficient when storing large amounts of data.

[espruino-discuss]

Posted at 2018-03-08 by 7oo1er

Thank you for support and all answers, I'm happy with it!