combine()?

[possibly]

So I am making this game (same one as before) and am still using Fixed2DArray. I would like to have my Fixed2DArray grow as the player 'explores' it, kinda like how minecraft generates new terrain as the player travels around the world. Arrays in Javascript have concat(), but i'd like Fixed2DArray to have a concat that works a bit differently. Im thinking about calling Fixed2DArray's concat()-equivalent combine().

For example:

var fixedArray = require('..');
var fa1 = new fixedArray(2,2,0);
var fa2 = new fixedArray(2,2,1);
var fa3 = fa1.combine(fa2);
console.log(fa3._grid); 

Output

[
[0, 0, 1, 1],
[0, 0, 1, 1]
]

HOWEVER, what if I wanted to combine fa2 to the top of fa1, as opposed to the right? Like so:

[
[1, 1],
[1, 1],
[0, 0],
[0, 0],
]

wowowowow.

Then using combine would like more like

var fa3 = fa1.combine(fa2, 'top'); 
//left, right, top, bottom

But what about fixedArrays of a different sizes? For example,

var fixedArray = require('..');
var fa4 = new fixedArray(2,2,4);
var smallerFA5 = new fixedArray(1,1,5);
var fa6 = fa4.combine(smallerFA5);
console.log(fa6._grid); 

What should fa6 be? Outputting a Fixed2DArray might be strange since the combination of a 2x2 Fixed2DArray and a 1x1 Fixed2DArray leads to a "Staggered2DArray", not a fixed2DArray!

Example of "Staggered2DArray":

[
[4, 4, 5]
[4, 4]
]

I have a few ideas, though I am not sure which one is best:

1. Fixed2DArray's functions still work if the ._grid variable is technically "staggered." Therefore, the output of fa6 can just be a Fixed2DArray that has had its ._grid variable played with.

2. Only allow combine() to "combine" Fixed2DArrays of the same height and width. I think this is how typical mathematics matrices work?

3. Keep the ._grid "fixed" but use some filler variable. For example, the output of fa6 could be:

[
[4, 4, 5],
[4, 4, null]
]

if the filler variable was null. combine() could have an optional fillerVar argument as well, so the user can define whatever fillerVar works for them.

I dont like option 1. Option 2 is easiest. Option 3 is kinda cool, but I would like to notify the coders in some way that "hey, these Fixed2DArrays are different if you werent aware!"

[tillarnold]

Yes I don't like option 1 as well. Option 3 with an optional fillerVar argument sounds like the most flexible option. Option 2 sounds ok as well.

[possibly]

After re-reading this, I think I agree with you. Option 2 sounds the most intuitive for an object called Fixed2DArray.