63 lines
2.1 KiB
Markdown
63 lines
2.1 KiB
Markdown
# @fastify/error
|
|
|
|
|
|
[](https://www.npmjs.com/package/@fastify/error)
|
|
[](https://standardjs.com/)
|
|
|
|
A small utility, used by Fastify itself, for generating consistent error objects across your codebase and plugins.
|
|
|
|
### Install
|
|
```
|
|
npm i @fastify/error
|
|
```
|
|
|
|
### Usage
|
|
|
|
The module exports a function that you can use for consistent error objects, it takes 4 parameters:
|
|
|
|
```
|
|
createError(code, message [, statusCode [, Base]])
|
|
```
|
|
|
|
- `code` (`string`, required) - The error code, you can access it later with `error.code`. For consistency, we recommend prefixing plugin error codes with `FST_`
|
|
- `message` (`string`, required) - The error message. You can also use interpolated strings for formatting the message.
|
|
- `statusCode` (`number`, optional) - The status code that Fastify will use if the error is sent via HTTP.
|
|
- `Base` (`ErrorConstructor`, optional) - The base error object that will be used. (eg `TypeError`, `RangeError`)
|
|
|
|
```js
|
|
const createError = require('@fastify/error')
|
|
const CustomError = createError('ERROR_CODE', 'Hello')
|
|
console.log(new CustomError()) // error.message => 'Hello'
|
|
```
|
|
|
|
How to use an interpolated string:
|
|
```js
|
|
const createError = require('@fastify/error')
|
|
const CustomError = createError('ERROR_CODE', 'Hello %s')
|
|
console.log(new CustomError('world')) // error.message => 'Hello world'
|
|
```
|
|
|
|
How to add cause:
|
|
```js
|
|
const createError = require('@fastify/error')
|
|
const CustomError = createError('ERROR_CODE', 'Hello %s')
|
|
console.log(new CustomError('world', {cause: new Error('cause')}))
|
|
// error.message => 'Hello world'
|
|
// error.cause => Error('cause')
|
|
```
|
|
|
|
### TypeScript
|
|
|
|
It is possible to limit your error constructor with a generic type using TypeScript:
|
|
|
|
```ts
|
|
const CustomError = createError<[string]>('ERROR_CODE', 'Hello %s')
|
|
new CustomError('world')
|
|
//@ts-expect-error
|
|
new CustomError(1)
|
|
```
|
|
|
|
## License
|
|
|
|
Licensed under [MIT](./LICENSE).
|