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Initially execute all the functions until the queue fills up.
Every time a function resolves, add a new promise to the queue if possible.
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Jot down your thoughts, approach, and key learnings
Yes, Promise Pool-style problems are common in JavaScript interviews, especially for frontend or Node.js roles. They test understanding of promises, async/await, concurrency control, and task scheduling.
Limiting concurrency prevents too many asynchronous operations from running at once, which could overwhelm system resources or APIs. A promise pool ensures efficient execution while respecting limits like network or server capacity.
A simple index counter combined with an array of functions works well. The index tracks the next task to execute while workers pull tasks sequentially. This avoids complex queues while still maintaining controlled concurrency.
The optimal approach uses a concurrency-controlled worker pool. Start up to n asynchronous workers and let each worker execute the next available task once it finishes the current one. This guarantees that no more than n promises run simultaneously.
