How do I cancel a network request with fun-task?

Define a computation function that returns a cancellation callback, then call `task.run()` and use the returned function to abort. The README explains computations with cleanup logic.

Fun-task vs Promises: when should I use which?

Use fun-task for cancellable, lazy async operations with functional composition. Choose Promises for fire-and-forget async where shared results and immediate execution are sufficient, as per the README's comparison.

How to convert a Promise to a Task in fun-task?

Wrap the Promise in a computation function that calls resolve/reject, but note the Promise starts immediately. There's no built-in method, so manual wrapping is needed, which loses some lazy benefits.

Does fun-task work with async/await?

Not directly, as Tasks aren't Promises. You can convert Tasks to Promises for use with async/await, but this sacrifices cancellation capabilities and lazy execution.

Is fun-task good for React applications?

It can be used, but you'll need to handle cancellation manually in useEffect cleanup functions. React's ecosystem is more optimized for Promises, so integration requires extra effort.

What are the performance costs of using fun-task?

Tasks add abstraction layers for lazy evaluation and cancellation, which may introduce slight overhead compared to native Promises, but the trade-off is fine-grained control for complex async workflows.

Open-Awesome

fun-task

MITJavaScriptv1.5.2

A functional abstraction for managing asynchronous computations in JavaScript with cancellation support.

GitHub

374 stars18 forks0 contributors

What is fun-task?

Fun-task is a JavaScript library that provides a Task abstraction for managing asynchronous computations with cancellation support. It solves the problem of controlling async operations by allowing developers to start, cancel, and rerun computations, unlike Promises which only represent results. It is based on functional programming principles and offers a composable API for complex async workflows.

Target Audience

JavaScript developers building applications that require fine-grained control over asynchronous operations, such as cancellable network requests, complex async workflows, or functional programming enthusiasts.

Value Proposition

Developers choose Fun-task over alternatives like Promises for its cancellation capabilities, lazy execution, and adherence to functional programming patterns, making it ideal for scenarios where async lifecycle management is critical.

Overview

Abstraction for managing asynchronous code in JS

Use Cases

Best For

Implementing cancellable network requests or timeouts
Building complex asynchronous workflows with functional composition
Managing side effects in functional JavaScript applications
Creating reusable async operations that need to be run multiple times
Integrating with Fantasy Land or Static Land compatible libraries
Developing applications requiring explicit control over async execution

Not Ideal For

Applications where multiple consumers need to share the same async result without rerunning computations
Simple async workflows that rely on native Promises and async/await without needing cancellation
Teams not using Flow or functional programming patterns, seeking minimal abstraction overhead
Environments requiring immediate execution of async operations, as Tasks are lazy by default

Pros & Cons

Pros

Cancellation Support

Tasks can be terminated before completion with optional cleanup logic, addressing a key limitation of native Promises, as highlighted in the README's comparison.

Functional Composition

Implements Fantasy Land and Static Land specifications, enabling monadic operations like map and chain for composable async workflows.

Lazy Execution

Computations only start when `task.run()` is called, allowing deferred execution and better control over async lifecycle, unlike Promises which start immediately.

Type Safety

Includes built-in Flow type definitions for static type checking, making it suitable for type-safe JavaScript projects.

Cons

Result Inconsistency

Tasks spawn separate computations for each run, potentially yielding different results for the same task, whereas Promises guarantee shared results, as admitted in the README.

FP Learning Curve

Requires understanding of functional programming concepts like monads and functors, which can be a barrier for developers not familiar with FP patterns.

Limited Ecosystem

As a niche library, it has fewer integrations, community resources, and tooling support compared to native Promises or mainstream async libraries.

Frequently Asked Questions

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