Explain how Promise.all waits for all requests to complete in your recursive solution. Why might the current implementation return an incomplete result?

Promise.all accepts an array of promises and returns a new promise that resolves when all promises in the array are successfully fulfilled, or rejects upon the first rejection. In a recursive solution, if at each recursion step promises are collected into an array and passed to Promise.all, it will wait for all these promises to resolve at all recursion levels.

However, the current implementation may return incomplete results if:

• At some recursion level, promises are not collected correctly, and some requests are not included in the array for Promise.all.
• The recursion does not wait for the completion of nested calls, meaning Promise.all is called before all recursive calls have formed their promises.
• Errors in one of the promises cause Promise.all to reject, and subsequent results are not collected.

For example, if the recursive function does not return a promise that aggregates all nested promises, Promise.all will only wait for some requests, leaving others unresolved. To avoid this, at each recursion level, you should return Promise.all with an array of all promises, including those from recursive calls.