How do I cancel a delay using AbortSignal?

Pass an AbortSignal to the delay function's options. When aborted, the promise rejects with an AbortError, as shown in the README's code example for controlled cancellation.

delay vs native setTimeout: which should I use?

Use delay for promise-based workflows, abort support, random delays, or unlimited lengths. Choose setTimeout for simple, callback-based delays or when minimizing dependencies is critical.

Can delay handle random wait times for web scraping?

Yes, use the rangeDelay function to generate delays between specified minimum and maximum milliseconds, which helps avoid detection by making timing unpredictable.

How to mock delays in tests with delay?

Use the createDelay function to inject custom setTimeout and clearTimeout functions, allowing you to stub timers for precise control in testing environments.

Is delay compatible with both Node.js and browsers?

Yes, delay is designed to work in both environments, providing consistent timing utilities, though Node.js users might prefer native options as noted in the README tip.

What's the difference between delay and p-timeout?

Delay creates delays with features like random ranges and value resolution, while p-timeout sets timeouts on existing promises to reject after a delay, serving complementary purposes in async workflows.

Open-Awesome

delay

MITJavaScriptv7.0.0

A promise-based utility for delaying execution with support for abort signals, random delays, and unlimited timeout lengths.

GitHub

624 stars37 forks0 contributors

What is delay?

Delay is a JavaScript library that provides promise-based utilities for delaying execution in asynchronous code. It solves the problem of managing timed operations in promise chains with features like abort signals, random delays, and support for unlimited timeout lengths that native `setTimeout` doesn't offer.

Target Audience

JavaScript developers working with async/await patterns who need reliable timing utilities for testing, web scraping, animations, or any scenario requiring controlled delays in promise-based workflows.

Value Proposition

Developers choose Delay over native timing functions because it provides a cleaner promise-based API, supports modern features like AbortSignal for cancellation, offers unlimited delay lengths, and includes utilities like random delays that are particularly useful for testing and avoiding predictable patterns.

Overview

Delay a promise a specified amount of time

Use Cases

Best For

Adding controlled delays in async/await workflows
Testing asynchronous code with predictable timing
Web scraping with randomized delays to avoid detection
Creating animations with promise-based timing control
Implementing timeout patterns with cancellation support
Simulating network latency in development environments

Not Ideal For

Node.js-exclusive projects where native timers/promises meet all needs
Performance-critical applications requiring microsecond precision or minimal promise overhead
Simple scripts or demos where adding a dependency for basic delays is overkill
Systems needing built-in interval or scheduling functionality beyond one-off delays

Pros & Cons

Pros

Promise-Native Integration

Returns promises that seamlessly work with async/await syntax, simplifying asynchronous code flow as shown in the basic usage example.

Abort Signal Cancellation

Supports standard AbortSignal for canceling delays, providing better control over asynchronous operations compared to manual clearTimeout, with clear error handling.

Random Delay Ranges

Includes rangeDelay for generating delays between min and max values, explicitly designed for testing and web scraping to avoid predictable patterns.

Unlimited Timeout Support

Allows delays longer than the native 24.8-day setTimeout limit, enabling long-term timing without workarounds.

Cons

Redundant for Node.js Natives

The README notes that Node.js users can use native timers/promises, making Delay unnecessary unless browser support or extra features like random delays are required.

No Interval Support

Focuses solely on delays without built-in methods for intervals, forcing developers to implement or use additional libraries for repeated timing tasks.

Dependency Overhead

Adds an external package where simple use cases might be handled with native setTimeout, introducing extra complexity and potential performance overhead in high-frequency scenarios.

Frequently Asked Questions

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