fastify-esm-loader

An esm-based loader for your Fastify applications.

npm i fastify-esm-loader --save

Features

Automatically discovers route handlers from file system
Introduces handy idioms and helpers for dependency injection
Forces a clean, well organized style for route handler definitions

Example

npm i
cd example/
node index.js

Usage

import { join } from 'path'
import Fastify from 'fastify'
import FastifyESMLoader from 'fastify-esm-loader'
 
const fastify = Fastify({
  logger: {
    prettyPrint: {
      levelFirst: true,
    },
  },
})
 
fastify.register(FastifyESMLoader, {
  baseDir: join(__dirname, 'routes'),
  injections: {
    someRootHelper () {
      return 'foobar'
    }
  }
})

You can also use injections to make available things like db and redis.

Check examples/index.js and examples/main.js for the full boilerplate.

Assuming baseDir is routes, fastify-esm-loader will recursively look for index.js files use them to register routes, at any depth. Take for example project/routes/users/index.js -- here users is a route group -- you can have multiple route groups under baseDir. This file must export a function with a signature like this:

export default function ({ fastify, self, env }) {
  fastify.get('/users/all', self.listUsers)
  fastify.get('/users/:id', self.getUser)
  fastify.post('/users/', self.createUser)
}

For that to work, you'd have to have three files under routes/users:

project/routes/users/listUser.js
project/routes/users/createUser.js
project/routes/users/createUser.js

And each of these files, export a default function that is then used as a route handler. The loader will make them available in self in the main route definition function (users/index.js), so that you can easily tweak the mapping.

The mechanics described above will work for both top-level files and subfolders.

That means the following setup work would the same:

project/routes/index.js
project/routes/topLevelMethod.js
project/routes/users/listUser.js
project/routes/users/createUser.js
project/routes/users/createUser.js

Handlers

There are two ways to define a handler:

A function that returns the handler, useful for injections (and environment access):

export default ({ env }) => {
  return async (request, reply) => {
    reply.send(await auth.authenticate(env.JWT_TOKEN))
  }
}

A direct handler export:

export default async function (request, reply) {
  reply.send({ message: 'No injections needed here' })
}

Environment shorthand

NODE_ENV is used to populate env.$node_env (lowercase, prefixed with $).

This allows for checks such as this:

export default ({ env, fastify, self }) => {
  if (env.$staging) {
    fastify.get('/staging-only', self.stagingOnly)
  }
}

License

MIT

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