rsp/node-caught

A function to avoid UnhandledPromiseRejectionWarning and PromiseRejectionHandledWarning

node caught

This module lets you attach empty rejcetion handlers to promises to avoid certain warnings that will be fatal errors in next versions of Node.

Since version 0.1.0 it supports TypeScript thanks to Wil Lee.

For a version for Deno, see: https://deno.land/x/caught

More info

Doing something like this:

var p = Promise.reject(0);

setTimeout(() => p.catch(e => console.error('caught')), 0);

will generate a lot of helpful warnings:

(node:13548) UnhandledPromiseRejectionWarning: Unhandled promise rejection (rejection id: 1): 0
(node:13548) DeprecationWarning: Unhandled promise rejections are deprecated. In the future, promise rejections that are not handled will terminate the Node.js process with a non-zero exit code.
(node:13548) PromiseRejectionHandledWarning: Promise rejection was handled asynchronously (rejection id: 1)

This module lets you write:

var p = caught(Promise.reject(0));

setTimeout(() => p.catch(e => console.error('caught')), 0);

to ignore those warnings on a per-promise basis.

Use at your own risk.

Background

For more info see this answer on Stack Overflow:

• Should I refrain from handling Promise rejection asynchronously?

Installation

To use in your projects:

npm install caught --save

Usage

var caught = require('caught');

var p = caught(Promise.reject(0));

Note that it is not the same as writing:

var p = Promise.reject(0).catch(() => {});

which would not return the original promise and wouldn't let you add catch handlers later.

Issues

For any bug reports or feature requests please post an issue on GitHub.

Author

Rafał Pocztarski

Contributors

• Wil Lee (added TypeScript support in PR #1)

License

MIT License (Expat). See LICENSE.md for details.