ehmicky
💻 🎨 🤔 📖
Steven Vachon
💬
Hongarc
📖 💻
[](https://codecov.io/gh/ehmicky/log-process-errors)
[](https://travis-ci.org/ehmicky/log-process-errors)
[](https://www.npmjs.com/package/log-process-errors)
[](https://gitter.im/ehmicky/log-process-errors)
[](https://twitter.com/intent/follow?screen_name=ehmicky)
[](https://medium.com/@ehmicky)
[📰 Medium article.](https://medium.com/@ehmicky/node-js-process-errors-are-broken-193980f0a77b)
Show some ❤️ to Node.js process errors.
Node.js prints process errors
([`uncaughtException`](https://nodejs.org/api/process.html#process_event_uncaughtexception),
[`warning`](https://nodejs.org/api/process.html#process_event_warning),
[`unhandledRejection`](https://nodejs.org/api/process.html#process_event_unhandledrejection),
[`rejectionHandled`](https://nodejs.org/api/process.html#process_event_rejectionhandled))
on the console which is very useful. Unfortunately those errors:
- do not show stack traces for
[`warning`](https://nodejs.org/api/process.html#process_event_warning) and
[`rejectionHandled`](https://nodejs.org/api/process.html#process_event_rejectionhandled)
making them hard to debug.
- do not include
[`multipleResolves`](https://nodejs.org/api/process.html#process_event_multipleresolves)
errors (when a promise is resolved/rejected twice).
- are inconvenient to [log to an external service](docs/API.md#log).
- are hard to [test](docs/API.md#testing).
- cannot be conditionally skipped.
- are printed each time an error is repeated (except for
[`warning`](https://nodejs.org/api/process.html#process_event_warning)).
- are not human-friendly.
`log-process-errors` fixes all those issues.
Without `log-process-errors`:
With `log-process-errors`:
# Use cases
- Proper **logging** of process errors in production.
- **Debugging** of process errors in development.
- Automated **testing** of process errors.
# Demo
You can try this library:
- either directly
[in your browser](https://repl.it/@ehmicky/log-process-errors).
- or by executing the [`examples` files](examples/README.md) in a terminal.
# Install
Production code (e.g. a server) can install this either as a production or
development dependency:
```bash
npm install log-process-errors
```
However, libraries should install this as a development dependency:
```bash
npm install -D log-process-errors
```
This is because logging is modified globally and libraries users might not
expect this side-effect. Also, this might lead to conflicts between libraries.
# Usage
There are two ways to load this library. The first is to use the
[`node -r` CLI flag](https://nodejs.org/api/cli.html#cli_r_require_module):
```bash
node -r log-process-errors/build/register ...
```
The second is:
```js
const logProcessErrors = require('log-process-errors')
logProcessErrors(options)
```
`logProcessErrors()` should be called as early as possible in the code, before
other `require`/`import` statements.
# Options
`options` is an optional object with the following properties.
## log
_Type_: `function(error, level, originalError)`ehmicky 💻 🎨 🤔 📖 | Steven Vachon 💬 | Hongarc 📖 💻 |