Utility for number ranges

src/utils/numbers.test.ts

@@ -0,0 +1,15 @@
+import { numberRange } from "./numbers";
+
+describe("numberRange", () => {
+  it("lists numbers in positive range", () => {
+    expect(numberRange(0, 5)).toEqual([0, 1, 2, 3, 4, 5]);
+  });
+
+  it("lists numbers in negative range", () => {
+    expect(numberRange(-5, 5)).toEqual([-5, -4, -3, -2, -1, 0, 1, 2, 3, 4, 5]);
+  });
+
+  it("lists numbers when from/to are backwards", () => {
+    expect(numberRange(5, 0)).toEqual([0, 1, 2, 3, 4, 5]);
+  });
+});

src/utils/numbers.ts

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+/** Generate array with integers between `from` and `to`. */
+export function numberRange(from: number, to: number): number[] {
+  if (from > to) {
+    [to, from] = [from, to];
+  }
+  return Array(to - from + 1)
+    .fill(0)
+    .map((_, i) => from + i);
+}