[](https://www.npmjs.com/package/modern-errors-process) [](/src/main.d.ts) [](https://codecov.io/gh/ehmicky/modern-errors-process) [](https://fosstodon.org/@ehmicky) [](https://medium.com/@ehmicky) [`modern-errors`](https://github.com/ehmicky/modern-errors) [plugin](https://github.com/ehmicky/modern-errors#-plugins) to handle process errors. This improves process errors: [uncaught](https://nodejs.org/api/process.html#process_event_uncaughtexception) exceptions, [unhandled](https://nodejs.org/api/process.html#process_event_unhandledrejection) promises, promises [handled too late](https://nodejs.org/api/process.html#process_event_rejectionhandled) and [warnings](https://nodejs.org/api/process.html#process_event_warning). # Features - Stack traces for warnings and [`rejectionHandled`](https://nodejs.org/api/process.html#process_event_rejectionhandled) - [Single event handler](#onerror) for all process errors - Set any process error's class to [`UnknownError`](https://github.com/ehmicky/modern-errors#-unknown-errors) - Ignore [duplicate](#onerror) process errors - [Normalize](#error) invalid errors - [Process exit](#exit) is graceful and can be prevented # Example [Adding the plugin](https://github.com/ehmicky/modern-errors#adding-plugins) to [`modern-errors`](https://github.com/ehmicky/modern-errors). ```js import ModernError from 'modern-errors' import modernErrorsProcess from 'modern-errors-process' export const BaseError = ModernError.subclass('BaseError', { plugins: [modernErrorsProcess], }) export const UnknownError = BaseError.subclass('UnknownError') // ... ``` [Initializing](#errorclasslogprocess) the process error handler. ```js UnknownError.logProcess() ``` # Install Production code (e.g. a server) can install this either as a production or as a development dependency. ```bash npm install modern-errors-process ``` However, libraries should install this as a development dependency. ```bash npm install -D modern-errors-process ``` This is because logging is modified globally and libraries users might not expect this side-effect. Also, this might lead to conflicts between libraries. This package requires Node.js >=18.18.0. This is an ES module. It must be loaded using [an `import` or `import()` statement](https://gist.github.com/sindresorhus/a39789f98801d908bbc7ff3ecc99d99c), not `require()`. If TypeScript is used, it must be configured to [output ES modules](https://www.typescriptlang.org/docs/handbook/esm-node.html), not CommonJS. # API ## modernErrorsProcess _Type_: `Plugin` Plugin object to pass to the [`plugins` option](https://github.com/ehmicky/modern-errors#adding-plugins) of `ErrorClass.subclass()`. ## ErrorClass.logProcess() _Return value_: `() => void` Start handling process errors. The return value restores Node.js default behavior. ```js const restore = UnknownError.logProcess() restore() ``` ## Options _Type_: `object` ### exit _Type_: `boolean` Whether to exit the process on [uncaught exceptions](https://nodejs.org/api/process.html#process_event_uncaughtexception) or [unhandled promises](https://nodejs.org/api/process.html#process_event_unhandledrejection). This is `false` by default if other libraries are listening to those events, so they can perform the exit instead. Otherwise, this is `true`. If some tasks are still ongoing, the exit waits for them to complete up to 3 seconds. ### onError _Type_: `(error, event) => Promise | void`\ _Default_: `console.error(error)` Function called once per process error. Duplicate process errors are ignored. #### error _Type_: [`UnknownError`](https://github.com/ehmicky/modern-errors#-unknown-errors) The process error. This is guaranteed to be a [normalized](https://github.com/ehmicky/normalize-exception) [`UnknownError`](https://github.com/ehmicky/modern-errors#-unknown-errors) instance. A short description of the [event](#event) is also appended to its message. #### event _Type_: `Event` Process event name among: [`'uncaughtException'`](https://nodejs.org/api/process.html#process_event_uncaughtexception), [`'unhandledRejection'`](https://nodejs.org/api/process.html#process_event_unhandledrejection), [`'rejectionHandled'`](https://nodejs.org/api/process.html#process_event_rejectionhandled), [`'warning'`](https://nodejs.org/api/process.html#process_event_warning). ## Configuration [Options](#options) must be passed either to [`ModernError.subclass()`](https://github.com/ehmicky/modern-errors#options-1). ```js export const BaseError = ModernError.subclass('BaseError', { plugins: [modernErrorsProcess], process: options, }) ``` To [`UnknownError.subclass()`](https://github.com/ehmicky/modern-errors#options-1). ```js export const UnknownError = BaseError.subclass('UnknownError', { process: options, }) ``` Or to [`UnknownError.logProcess()`](#errorclasslogprocess). ```js UnknownError.logProcess(options) ``` # Related projects - [`log-process-errors`](https://github.com/ehmicky/log-process-errors): Show some ❤ to Node.js process errors - [`modern-errors`](https://github.com/ehmicky/modern-errors): Handle errors in a simple, stable, consistent way - [`modern-errors-cli`](https://github.com/ehmicky/modern-errors-cli): Handle errors in CLI modules - [`modern-errors-bugs`](https://github.com/ehmicky/modern-errors-bugs): Print where to report bugs - [`modern-errors-serialize`](https://github.com/ehmicky/modern-errors-serialize): Serialize/parse errors - [`modern-errors-clean`](https://github.com/ehmicky/modern-errors-clean): Clean stack traces - [`modern-errors-http`](https://github.com/ehmicky/modern-errors-http): Create HTTP error responses - [`modern-errors-winston`](https://github.com/ehmicky/modern-errors-winston): Log errors with Winston - [`modern-errors-switch`](https://github.com/ehmicky/modern-errors-switch): Execute class-specific logic # Support For any question, _don't hesitate_ to [submit an issue on GitHub](../../issues). Everyone is welcome regardless of personal background. We enforce a [Code of conduct](CODE_OF_CONDUCT.md) in order to promote a positive and inclusive environment. # Contributing This project was made with ❤️. The simplest way to give back is by starring and sharing it online. If the documentation is unclear or has a typo, please click on the page's `Edit` button (pencil icon) and suggest a correction. If you would like to help us fix a bug or add a new feature, please check our [guidelines](CONTRIBUTING.md). Pull requests are welcome!