🧪 Failing range

Author: UltiRequiem

range.test.ts

@@ -0,0 +1,19 @@
+import { range } from "./range.ts";
+import { assert } from "./testing.ts";
+
+Deno.test("[range]", () => {
+  const result = range(1, 3);
+  const expectedResult = [1, 2, 3];
+
+  for (let i = 0; i < 3; i++) {
+    assert(result[i] === expectedResult[i]);
+  }
+
+  const resultTwo = range(1, 10, 2);
+  const expectedResultTwo = [1, 3, 5, 7, 9];
+  console.log(resultTwo);
+
+  for (let i = 0; i < 3; i++) {
+    assert(resultTwo[i] === expectedResultTwo[i]);
+  }
+});

range.ts

@@ -0,0 +1,15 @@
+function areNumbers(values: unknown[]): values is number[] {
+  return values.every(Number.isInteger);
+}
+
+export function range(start: number, end: number, step = 1): number[] {
+  if (!areNumbers([start, end, step])) {
+    throw new TypeError("Exepected all parameters to be numbers.");
+  }
+
+  const length = end - start + 1;
+
+  let counter = 0;
+
+  return Array.from({ length }, () => (counter += step));
+}

testing.ts

@@ -1,5 +1,8 @@
-export function assert(condition: unknown): asserts condition is true {
+export function assert(
+  condition: unknown,
+  message = "Codition is false!"
+): asserts condition {
   if (!condition) {
-    throw new Error("Codition is false!");
+    throw new Error(message);
   }
 }