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https://github.com/fastify/fastify-plugin
Plugin helper for Fastify
https://github.com/fastify/fastify-plugin
encapsulation fastify fastify-library versioning
Last synced: 3 days ago
JSON representation
Plugin helper for Fastify
- Host: GitHub
- URL: https://github.com/fastify/fastify-plugin
- Owner: fastify
- License: mit
- Created: 2017-03-21T14:46:44.000Z (almost 8 years ago)
- Default Branch: master
- Last Pushed: 2024-12-08T22:03:03.000Z (14 days ago)
- Last Synced: 2024-12-12T05:04:37.732Z (10 days ago)
- Topics: encapsulation, fastify, fastify-library, versioning
- Language: JavaScript
- Homepage:
- Size: 210 KB
- Stars: 204
- Watchers: 15
- Forks: 43
- Open Issues: 5
-
Metadata Files:
- Readme: README.md
- License: LICENSE
Awesome Lists containing this project
README
# fastify-plugin
[](https://github.com/fastify/fastify-plugin/actions/workflows/ci.yml)
[](https://www.npmjs.com/package/fastify-plugin)
[](https://github.com/neostandard/neostandard)
`fastify-plugin` is a plugin helper for [Fastify](https://github.com/fastify/fastify).
When you build plugins for Fastify and you want them to be accessible in the same context where you require them, you have two ways:
1. Use the `skip-override` hidden property
2. Use this module
__Note: the v4.x series of this module covers Fastify v4__
__Note: the v2.x & v3.x series of this module covers Fastify v3. For Fastify v2 support, refer to the v1.x series.__
## Install
```sh
npm i fastify-plugin
```
## Usage
`fastify-plugin` can do three things for you:
- Add the `skip-override` hidden property
- Check the bare-minimum version of Fastify
- Pass some custom metadata of the plugin to Fastify
Example using a callback:
```js
const fp = require('fastify-plugin')
module.exports = fp(function (fastify, opts, done) {
// your plugin code
done()
})
```
Example using an [async](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/async_function) function:
```js
const fp = require('fastify-plugin')
// A callback function param is not required for async functions
module.exports = fp(async function (fastify, opts) {
// Wait for an async function to fulfill promise before proceeding
await exampleAsyncFunction()
})
```
## Metadata
In addition, if you use this module when creating new plugins, you can declare the dependencies, the name, and the expected Fastify version that your plugin needs.
#### Fastify version
If you need to set a bare-minimum version of Fastify for your plugin, just add the [semver](https://semver.org/) range that you need:
```js
const fp = require('fastify-plugin')
module.exports = fp(function (fastify, opts, done) {
// your plugin code
done()
}, { fastify: '5.x' })
```
If you need to check the Fastify version only, you can pass just the version string.
You can check [here](https://github.com/npm/node-semver#ranges) how to define a `semver` range.
#### Name
Fastify uses this option to validate the dependency graph, allowing it to ensure that no name collisions occur and making it possible to perform [dependency checks](https://github.com/fastify/fastify-plugin#dependencies).
```js
const fp = require('fastify-plugin')
function plugin (fastify, opts, done) {
// your plugin code
done()
}
module.exports = fp(plugin, {
fastify: '5.x',
name: 'your-plugin-name'
})
```
#### Dependencies
You can also check if the `plugins` and `decorators` that your plugin intend to use are present in the dependency graph.
> *Note:* This is the point where registering `name` of the plugins become important, because you can reference `plugin` dependencies by their [name](https://github.com/fastify/fastify-plugin#name).
```js
const fp = require('fastify-plugin')
function plugin (fastify, opts, done) {
// your plugin code
done()
}
module.exports = fp(plugin, {
fastify: '5.x',
decorators: {
fastify: ['plugin1', 'plugin2'],
reply: ['compress']
},
dependencies: ['plugin1-name', 'plugin2-name']
})
```
#### Encapsulate
By default, `fastify-plugin` breaks the [encapsulation](https://github.com/fastify/fastify/blob/HEAD/docs/Reference/Encapsulation.md) but you can optionally keep the plugin encapsulated.
This allows you to set the plugin's name and validate its dependencies without making the plugin accessible.
```js
const fp = require('fastify-plugin')
function plugin (fastify, opts, done) {
// the decorator is not accessible outside this plugin
fastify.decorate('util', function() {})
done()
}
module.exports = fp(plugin, {
name: 'my-encapsulated-plugin',
fastify: '5.x',
decorators: {
fastify: ['plugin1', 'plugin2'],
reply: ['compress']
},
dependencies: ['plugin1-name', 'plugin2-name'],
encapsulate: true
})
```
#### Bundlers and Typescript
`fastify-plugin` adds a `.default` and `[name]` property to the passed in function.
The type definition would have to be updated to leverage this.
## Known Issue: TypeScript Contextual Inference
[Documentation Reference](https://www.typescriptlang.org/docs/handbook/functions.html#inferring-the-types)
It is common for developers to inline their plugin with fastify-plugin such as:
```js
fp((fastify, opts, done) => { done() })
fp(async (fastify, opts) => { return })
```
TypeScript can sometimes infer the types of the arguments for these functions. Plugins in Fastify are recommended to be typed using either `FastifyPluginCallback` or `FastifyPluginAsync`. These two definitions only differ in two ways:
1. The third argument `done` (the callback part)
2. The return type `FastifyPluginCallback` or `FastifyPluginAsync`
At this time, TypeScript inference is not smart enough to differentiate by definition argument length alone.
Thus, if you are a TypeScript developer please use on the following patterns instead:
```ts
// Callback
// Assign type directly
const pluginCallback: FastifyPluginCallback = (fastify, options, done) => { }
fp(pluginCallback)
// or define your own function declaration that satisfies the existing definitions
const pluginCallbackWithTypes = (fastify: FastifyInstance, options: FastifyPluginOptions, done: (error?: FastifyError) => void): void => { }
fp(pluginCallbackWithTypes)
// or inline
fp((fastify: FastifyInstance, options: FastifyPluginOptions, done: (error?: FastifyError) => void): void => { })
// Async
// Assign type directly
const pluginAsync: FastifyPluginAsync = async (fastify, options) => { }
fp(pluginAsync)
// or define your own function declaration that satisfies the existing definitions
const pluginAsyncWithTypes = async (fastify: FastifyInstance, options: FastifyPluginOptions): Promise => { }
fp(pluginAsyncWithTypes)
// or inline
fp(async (fastify: FastifyInstance, options: FastifyPluginOptions): Promise => { })
```
## Acknowledgements
This project is kindly sponsored by:
- [nearForm](https://nearform.com)
- [LetzDoIt](https://www.letzdoitapp.com/)
## License
Licensed under [MIT](./LICENSE).