refactor(grid-iterators): update diagonalEnds2d()

- add `all` option to include first & last points

packages/grid-iterators/src/diagonal-ends.ts

@@ -3,23 +3,24 @@ import { diagonal2d } from "./diagonal.js";
 import { __opts } from "./utils.js";
 
 /**
- * Filtered version of {@link diagonal2d}, only including end points of
- * the diagonals, apart from the very first and last points: `[0,0]` and
- * `[cols-1, rows-1]`.
+ * Filtered version of {@link diagonal2d}, only including end points of the
+ * diagonals. Unless `all` option is enabled (default: false), the very first
+ * and last points are skipped, i.e. `[0,0]` and `[cols-1, rows-1]`.
  *
  * @remarks
  * `cols` and `rows` MUST be both >= 2.
  *
  * @param opts -
  */
-export function* diagonalEnds2d(opts: GridIterOpts) {
+export function* diagonalEnds2d(opts: GridIterOpts & { all: boolean }) {
 	const { cols, rows, tx } = __opts(opts);
 	const num = cols * rows - 1;
 	const maxX = cols - 1;
 	const maxY = rows - 1;
+	const check = opts.all ? (i: number) => i > 0 && i < num : () => true;
 	let i = 0;
 	for (let p of diagonal2d({ cols, rows })) {
-		if (i > 0 && i < num) {
+		if (check(i)) {
 			const [x, y] = p;
 			if (x === 0 || x === maxX || y === 0 || y === maxY) yield tx(x, y);
 		}

packages/grid-iterators/src/diagonal.ts

@@ -16,7 +16,7 @@ export function* diagonal2d(opts: GridIterOpts) {
 	const num = cols * rows - 1;
 	for (let x = 0, y = 0, nx = 1, ny = 0, i = 0; i <= num; i++) {
 		yield tx(x, y);
-		if (i != num) {
+		if (i !== num) {
 			do {
 				if (y === ny) {
 					y = 0;