chore: use generator for range utility (#8825)

* chore: use generator for range utility

* chore: update doc examples

* chore: fix spelling

* chore: fix typo

Co-authored-by: kodiakhq[bot] <49736102+kodiakhq[bot]@users.noreply.github.com>

packages/util/__tests__/range.test.ts

@@ -2,11 +2,15 @@ import { describe, test, expect } from 'vitest';
 import { range } from '../src/index.js';
 
 describe('range', () => {
-	test('GIVEN valid range THEN valid array is returned', () => {
+	test('GIVEN valid range and then valid numbers are returned', () => {
-		expect(range(0, 5)).toEqual([0, 1, 2, 3, 4, 5]);
+		expect([...range(5)]).toEqual([0, 1, 2, 3, 4]);
 	});
 
-	test('GIVEN valid range with step THEN valid array is returned', () => {
+	test('GIVEN valid range with start and end THEN valid numbers are returned', () => {
-		expect(range(0, 10, 2)).toEqual([0, 2, 4, 6, 8, 10]);
+		expect([...range({ start: 0, end: 5 })]).toEqual([0, 1, 2, 3, 4]);
+	});
+
+	test('GIVEN valid range with start, end and step THEN valid numbers are returned', () => {
+		expect([...range({ start: 0, end: 11, step: 2 })]).toEqual([0, 2, 4, 6, 8, 10]);
 	});
 });

packages/util/src/functions/range.ts

@@ -1,20 +1,61 @@
 /**
- * Yields the numbers in the given range as an array
+ * Options for creating a range
+ */
+export interface RangeOptions {
+	/**
+	 * The end of the range (exclusive)
+	 */
+	end: number;
+	/**
+	 * The start of the range (inclusive)
+	 */
+	start: number;
+	/**
+	 * The amount to increment by
+	 *
+	 * @defaultValue `1`
+	 */
+	step?: number;
+}
+
+/**
+ * A generator to yield numbers in a given range
  *
- * @param start - The start of the range
+ * @remarks
- * @param end - The end of the range (inclusive)
+ * This method is end-exclusive, for example the last number yielded by `range(5)` is 4. If you
- * @param step - The amount to increment between each number
+ * prefer for the end to be included add 1 to the range or `end` option.
+ * @param range - A number representing the the range to yield (exclusive) or an object with start, end and step
  * @example
  * Basic range
  * ```ts
- * range(3, 5); // [3, 4, 5]
+ * for (const number of range(5)) {
+ *  console.log(number);
+ * }
+ * // Prints 0, 1, 2, 3, 4
  * ```
  * @example
  * Range with a step
  * ```ts
- * range(3, 10, 2); // [3, 5, 7, 9]
+ * for (const number of range({ start: 3, end: 10, step: 2 })) {
+ * 	console.log(number);
+ * }
+ * // Prints 3, 5, 7, 9
  * ```
  */
-export function range(start: number, end: number, step = 1): number[] {
+export function* range(range: RangeOptions | number) {
-	return Array.from({ length: (end - start) / step + 1 }, (_, index) => start + index * step);
+	let rangeEnd: number;
+	let start = 0;
+	let step = 1;
+
+	if (typeof range === 'number') {
+		rangeEnd = range;
+	} else {
+		start = range.start;
+		rangeEnd = range.end;
+		step = range.step ?? 1;
+	}
+
+	for (let index = start; index < rangeEnd; index += step) {
+		yield index;
+	}
 }

packages/ws/src/ws/WebSocketManager.ts

@@ -264,11 +264,12 @@ export class WebSocketManager extends AsyncEventEmitter<ManagerShardEventsMap> {
 			if (Array.isArray(this.options.shardIds)) {
 				shardIds = this.options.shardIds;
 			} else {
-				shardIds = range(this.options.shardIds.start, this.options.shardIds.end);
+				const { start, end } = this.options.shardIds;
+				shardIds = [...range({ start, end: end + 1 })];
 			}
 		} else {
 			const data = await this.fetchGatewayInformation();
-			shardIds = range(0, (this.options.shardCount ?? data.shards) - 1);
+			shardIds = [...range(this.options.shardCount ?? data.shards)];
 		}
 
 		this.shardIds = shardIds;