https://github.com/conjurelabs/err
Extending the native error constructor
https://github.com/conjurelabs/err
error-handling node
Last synced: 3 months ago
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Extending the native error constructor
- Host: GitHub
- URL: https://github.com/conjurelabs/err
- Owner: ConjureLabs
- License: mit
- Created: 2018-02-01T00:41:27.000Z (over 7 years ago)
- Default Branch: master
- Last Pushed: 2018-10-06T19:22:35.000Z (over 6 years ago)
- Last Synced: 2025-03-05T00:34:17.747Z (3 months ago)
- Topics: error-handling, node
- Language: JavaScript
- Size: 46.9 KB
- Stars: 1
- Watchers: 3
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE
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README
## Errors
[](https://circleci.com/gh/ConjureLabs/err/tree/master)
Extending native errors, to give a little more context.
This is useful for differentiating between server (5xx) and user (4xx) errors. As well as making sure internal vs. public-facing error messages are different.
### Install
```sh
npm install --save @conjurelabs/err
```
### Usage
```js
const { ConjureError } = require('@conjurelabs/err')
throw new ConjureError('something happened')
```
### Public-Facing Errors
Internal error dialogs may not be appropriate for end users. Default 'public' errors are set on every Conjure error.
```js
const { NotFoundError } = require('@conjurelabs/err')
const err = new NotFoundError('sensitive message')
console.log(err.message) // 'sensitive message'
console.log(err.publicMessage) // 'A needed resource was not found'
```
This can be used to pass back non-sensitive errors to the client, while still logging actual error messages internally.
```js
// in a final express route handler
server.use((err, req, res, next) => {
if (!err) {
return next()
}
console.log(err) // will log true error message & stack trace
if (err instanceof ConjureError) {
return res.status(err.httpStatusCode).send({ message: err.publicMessage })
}
// if a native (non ConjureError), then 500
res.status(500).send({ message: 'An error occurred '})
})
```
You can signal that a set error message is okay for public users, by passing `public: true` in an options argument.
```js
const err = new NotFoundError('The file you have requested is not present', { public: true })
```
This will set `.publicMessage` to `'The file you have requested is not present'`
### HTTP Status Codes
Similar to 'public' errors, you may also want to know what http status code an error should associate to.
```js
const { PermissionsError } = require('@conjurelabs/err')
const err = new PermissionsError(`User doesn't have access`)
console.log(err.httpStatusCode) // 403
```
### Wrapping a Native Error
If you want to extend a native error, you can pass in the entire `err` instance.
```js
const { PermissionsError } = require('@conjurelabs/err')
try {
await checkPermissions()
} catch(err) {
throw new PermissionsError(err)
}
```
### Tests
```sh
npm test
npm run lint
```