sindresorhus/p-queue
P Queue
p-queue is a JavaScript promise queue and concurrent task scheduler designed to limit the number of active asynchronous operations. It serves as an asynchronous rate limiter and promise lifecycle manager to prevent resource exhaustion.
The project distinguishes itself through priority-based task scheduling and token-bucket rate limiting to control execution frequency. It integrates with abort signals for task cancellation and provides mechanisms to pause, resume, and clear pending operations.
The tool covers broader traffic management capabilities including operation timeouts and concurrency limiting. It also includes monitoring primitives to track queue state and pending task counts, as well as synchronization for queue idling.
Features
- Asynchronous Task Schedulers - Provides a comprehensive system for dispatching and executing asynchronous tasks with priority and concurrency control.
- Task Queues - Provides a JavaScript promise queue for managing asynchronous tasks with strict concurrency limits.
- Token Bucket Implementations - Implements a token-bucket algorithm to cap the execution frequency of tasks over a fixed time window.
- Queue Priority Scheduling - Supports priority-based task scheduling to ensure critical operations are processed before lower-priority ones.
- Concurrency Semaphores - Uses semaphore-like logic to limit the number of active promises running simultaneously.
- Concurrent Task Limiters - Caps the number of parallel tasks executing to manage system resource consumption.
- Concurrent Task Schedulers - Ships a scheduler that controls the number of active promises and manages task priority and timeouts.
- Task Priority Execution - Implements priority levels for tasks to ensure that critical work is executed before lower-priority operations.
- Rate Limiters - Implements application-level rate limiting using token bucket and fixed window algorithms.
- Concurrency Limiting - Restricts the number of concurrent asynchronous operations to prevent system resource exhaustion.
- Queue Pause and Resume Controls - Allows the queue to be paused and resumed to synchronize background work with application state.
- Graceful Queue Draining - Provides a promise that resolves only after all active and pending tasks are fully processed.
- AbortSignal Cancellations - Integrates with AbortSignals to allow both pending and active tasks to be cancelled immediately.
- AbortSignal Integrations - Provides integration with standard browser AbortSignals to trigger the immediate removal or termination of pending tasks.
- Async Operation Timeouts - Provides the ability to set maximum execution durations for queued tasks to prevent hanging operations.
- Idle State Synchronization - Provides a synchronization mechanism that resolves promises only after the queue is empty and all active tasks finish.
- API Rate Limiting - Controls the frequency of outgoing network requests to comply with external API rate limits.
- Promise Lifecycle Managers - Manages the lifecycle of promises including the ability to pause, resume, and clear pending operations.
- Concurrency Control - Manage promise execution with concurrency control.
- Promise Utilities - Manages promise execution with concurrency control.
- Works with AVA - Listed in the “Works with AVA” section of the Awesome Ava awesome list.
