@fastify/env

Fastify plugin to check environment variables

Install

npm i @fastify/env

Usage

1const fastify = require('fastify')()
2const fastifyEnv = require('@fastify/env')
3
4const schema = {
5  type: 'object',
6  required: [ 'PORT' ],
7  properties: {
8    PORT: {
9      type: 'string',
10      default: 3000
11    }
12  }
13}
14
15const options = {
16  confKey: 'config', // optional, default: 'config'
17  schema: schema,
18  data: data // optional, default: process.env
19}
20
21fastify
22  .register(fastifyEnv, options)
23  .ready((err) => {
24    if (err) console.error(err)
25
26    console.log(fastify.config) // or fastify[options.confKey]
27    console.log(fastify.getEnvs())
28    // output: { PORT: 3000 }
29  })

You can also use the function getEnvs() of the Request from within a handler function:

1fastify.get('/', (request, reply) => {
2    console.log(request.getEnvs())
3    // output: { PORT: 3000 }
4})

Note that the getEnvs decorators will not be added if they already exist.

This module is a wrapper around env-schema. To read an .env file you must set dotenv in the options:

1const options = {
2  dotenv: true // will read .env in root folder
3}
4
5// or, pass config options available on dotenv module
6const options = {
7  dotenv: {
8    path: `${__dirname}/.env`,
9    debug: true
10  }
11}
12

Using @fastify/env to configure other plugins

The @fastify/env plugin loads asynchronously. If you wish to use its values in a different plugin before the boot sequence, you need to make sure that:

1. @fastify/env is registered first.
2. Await the plugin registration or await after()

1await fastify.register(fastifyEnv)
2// fastify.config can be used in here

OR

1fastify.register(fastifyEnv)
2await fastify
3// fastify.config can be used in here

NB Support for additional properties in the schema is disabled for this plugin, with the additionalProperties flag set to false internally.

Typescript

In order to have typing for the fastify instance, you should either:

• use the declaration merging technique to enhance the FastifyInstance type with the property and its keys you have defined in the options:

1declare module 'fastify' {
2  interface FastifyInstance {
3    config: { // this should be same as the confKey in options
4      // specify your typing here
5      FOO: string
6    };
7  }
8}
9
10const fastify = Fastify()
11fastify.register(fastifyEnv)
12
13fastify.config.FOO // will be a string
14fastify.config.BAR // error: Property BAR does not exist on type { FOO: string }

• use the generic function getEnvs() to get the already typed object:

1type Envs = {
2  FOO: string
3}
4
5const fastify = Fastify()
6await fastify.register(fastifyEnv)
7
8const envs = fastify.getEnvs<Envs>() // envs will be of type Envs
9
10envs.FOO // will be a string
11envs.BAR // error: Property BAR does not exist on type Envs

If this is the case it is suggested to use json-schema-to-ts to have the type always synchronized with the actual schema.

Acknowledgements

Kindly sponsored by Mia Platform