Stitch multiple 2d arrays together to create a single (larger) 2d array.

stitch-2d-arrays.js

stitch2dArrays(arrs) {
	return arrs.map(row => {
		return row[0].map((col, i) => row.reduce((prev, current) => prev.concat(current[i]), []));
	}).reduce((prev, current) => prev.concat(current), []);
}

let arr = [[0, 0, 1],
	[0, 0, 1],
	[0, 0, 1]];
 		   
let stitch = [[arr, arr], 
  	[arr, arr]];

let output = stitch2dArrays(stitch);

/* output looks like this:

output = [[0, 0, 1, 0, 0, 1],
	[0, 0, 1, 0, 0, 1],
	[0, 0, 1, 0, 0, 1],
	[0, 0, 1, 0, 0, 1],
	[0, 0, 1, 0, 0, 1],
	[0, 0, 1, 0, 0, 1]];
 		  
Useful for procedurally generated game maps!

*/