Uncaught-extender NPM

uncaughtException & unhandledRejection Extender

Extends uncaughtException and unhandledRejection with custom listeners

Usage

Use the native uncaughtException or 'unhandledRejection' to setup:

IMPORTANT! ensure this is declared as early as possible in your execution cycle

const { uncaughtException, unhandledRejection} = require('uncaught-extender')

process.on('uncaughtException', uncaughtException)
process.on('unhandledRejection', unhandledRejection)

Start listening to any event type that matches your expected Error name:

// specificy your listeners for uncaught exceptions
process.on('uncaughtException:*', error => {}) // catch-all event listener
process.on('uncaughtException:Error', error => {})
process.on('uncaughtException:TypeError', error => {})
process.on('uncaughtException:CustomError', error => {})
process.on('uncaughtException:DataBaseError', error => {})

// specificy your listeners for rejected promises
process.on('unhandledRejection:*', error => {}) // catch-all event listener
process.on('unhandledRejection:Error', error => {})
process.on('unhandledRejection:TypeError', error => {})
process.on('unhandledRejection:CustomError', error => {})
process.on('unhandledRejection:DataBaseError', error => {})

continue with building your business logic normally, and when an exception is thrown or a Promise is rejected without a catch that matches one of your listener functions, that function will be called with the Error object passed as the only argument.

If no match is found, the Error is thrown again to the main process.

Full Example

const { uncaughtException, unhandledRejection } = require('uncaught-extender')

process.on('uncaughtException', uncaughtException)
process.on('unhandledRejection', unhandledRejection)

process.on('unhandledRejection:Error', error => console.log(error.message))
process.on('uncaughtException:TypeError', error => console.log(error.message))

Promise.reject(new Error('this will be caught by unhandledRejection:Error'))

throw new TypeError('this will be caught by uncaughtException:TypeError')

Warning: Using `'uncaughtException'` correctly

Note that 'uncaughtException' is a crude mechanism for exception handling intended to be used only as a last resort.

The event should not be used as an equivalent to On Error Resume Next. Unhandled exceptions inherently mean that an application is in an undefined state. Attempting to resume application code without properly recovering from the exception can cause additional unforeseen and unpredictable issues.

Learn more on the Official Node.js Documentation