♻️ Support steps

Author: UltiRequiem

range.test.ts

@@ -1,19 +1,20 @@
 import { range } from "./range.ts";
 import { assert } from "./testing.ts";
 
-Deno.test("[range]", () => {
+Deno.test("[range] Main", () => {
   const result = range(1, 3);
   const expectedResult = [1, 2, 3];
 
-  for (let i = 0; i < 3; i++) {
+  for (let i = 0; i < result.length; i++) {
     assert(result[i] === expectedResult[i]);
   }
+});
 
-  const resultTwo = range(1, 10, 2);
-  const expectedResultTwo = [1, 3, 5, 7, 9];
-  console.log(resultTwo);
+Deno.test("[range] Step", () => {
+  const result = range(1, 10, 2);
+  const expectedResult = [1, 3, 5, 7, 9];
 
-  for (let i = 0; i < 3; i++) {
-    assert(resultTwo[i] === expectedResultTwo[i]);
+  for (let i = 0; i < result.length; i++) {
+    assert(result[i] === expectedResult[i]);
   }
 });

range.ts

@@ -7,9 +7,17 @@ export function range(start: number, end: number, step = 1): number[] {
     throw new TypeError("Exepected all parameters to be numbers.");
   }
 
-  const length = end - start + 1;
+  const result: number[] = [];
 
-  let counter = 0;
+  const positiveStep = step >= 1;
 
-  return Array.from({ length }, () => (counter += step));
+  for (
+    let item = start;
+    item <= end;
+    positiveStep ? (item += step) : (item -= step)
+  ) {
+    result.push(item);
+  }
+
+  return result;
 }

testing.ts

@@ -1,6 +1,6 @@
 export function assert(
   condition: unknown,
-  message = "Codition is false!"
+  message = "Codition is false!",
 ): asserts condition {
   if (!condition) {
     throw new Error(message);