Implement a function mapAsyncLimit(arr, limit, asyncFn) that:
- Runs
asyncFn on each item of arr.
- Only runs
limit number of async operations concurrently.
- Returns a Promise that resolves to an array of results in the same order as input.
Input:
arr: Array of items.limit: Maximum number of concurrent async calls.asyncFn: Asynchronous function returning a promise.
Output:
- A promise that resolves to an array of results after processing all inputs using
asyncFn.
Example Inputs & Outputs
// Example: delayFn = x => new Promise(resolve => setTimeout(() => resolve(x * 2), 100))
await mapAsyncLimit([1, 2, 3, 4], 2, delayFn);
// Output: [2, 4, 6, 8]
// Example: limit = 1 behaves like sequential map
await mapAsyncLimit([1, 2, 3], 1, delayFn);
// Output: [2, 4, 6]
Constraints & Edge Cases
arr.length can be 0 → should return an empty array.limit should be >= 1.asyncFn may fail → should propagate the error.- Results must maintain input order.
- Should handle non-promise-returning functions gracefully (wrap in
Promise.resolve() if needed).
