rotate service and test cases; then updated index file

src/pages/list/rotate/service.ts

@@ -0,0 +1,48 @@
+import { isNumber } from 'utils/string';
+export type SplitOperatorType = 'symbol' | 'regex';
+
+function rotateArray(
+    array: string[],
+    step: number,
+    right: boolean): string[] {
+    const length = array.length;
+
+    // Normalize the step to be within the bounds of the array length
+    const normalizedPositions = ((step % length) + length) % length;
+
+    if (right) {
+        // Rotate right
+        return array.slice(-normalizedPositions).concat(array.slice(0, -normalizedPositions));
+    } else {
+        // Rotate left
+        return array.slice(normalizedPositions).concat(array.slice(0, normalizedPositions));
+    }
+}
+
+export function rotateList(
+    splitOperatorType: SplitOperatorType,
+    input: string,
+    splitSeparator: string,
+    joinSeparator: string,
+    right: boolean,
+    step?: number,
+): string {
+    let array: string[];
+    let rotatedArray: string[];
+    switch (splitOperatorType) {
+        case 'symbol':
+            array = input.split(splitSeparator);
+            break;
+        case 'regex':
+            array = input.split(new RegExp(splitSeparator));
+            break;
+    }
+    if (step !== undefined) {
+        if (step <= 0) {
+            throw new Error("Rotation step must be greater than zero.");
+        }
+        rotatedArray = rotateArray(array, step, right);
+        return rotatedArray.join(joinSeparator);
+    }
+    throw new Error("Rotation step contains non-digits.")
+}