Use the FS as your micro router
- ✅ 0 runtime dependencies
- ✅ < 100 loc
- ✅ little or no config
- ✅ parameterized paths
- ✅ parses query string
Micro is a fantastic library, but does not come with a router. After using next.js and really enjoying the "fs as router" paradigm, I thought it might be nice to do the same with micro.
This is the simplest approach I could think of to create a flexible router that stays out of your way with an intuitive API.
router usage
// index.js
const { send } = require('micro')
let match = require('fs-router')(__dirname + '/routes')
module.exports = async function(req, res) {
let matched = match(req)
if (matched) return await matched(req, res)
send(res, 404, { error: 'Not found' })
}
The above usage assumes you have a folder called routes
next to the index.js
file, that looks something like this:
routes/
├── foo
│ └── :param
│ └── thing.js
└── things
└── :id.js
the above tree would generate the following routes:
/foo/:param/thing
/things/:id
defining a route
// routes/foo/bar.js
const { send } = require('micro')
// respond to specific methods by exposing their verbs
module.exports.GET = async function(req, res) {
// fs-router decorates your req object with param and query hashes
send(res, 200, { params: req.params, query: req.query })
}
path parameters
// routes/foos/:id.js
const { send } = require('micro')
// responds to any method at /foos/* (but not /foos or /foos/bar/baz)
module.exports = async function(req, res) {
// params are always required when in a path, and the
send(res, 200, { id: req.params.id })
}
works great with async/await
const { send, json } = require('micro')
const qs = require('querystring')
require('isomorphic-fetch')
module.exports.GET = async function(req, res) {
const query = qs.stringify(req.query)
const data = await json(req)
const res = await fetch(`http://some-url.com?${query}`)
const response = await res.json()
send(res, 200, response)
}
typescript Use esModuleInterop and commonjs to import
// tsconfig.json
{
"compilerOptions": {
"module": "commonjs",
"esModuleInterop": true,
...config
}
}
use the RequestHandler
type from this lib
import { RequestHandler } from 'fs-router'
export const GET: RequestHandler = async (req, res) => {
// req.params and req.query will be typed correctly
send(res, 200, { params: req.params, query: req.query })
}
A full typescript example is available in the examples directory
priority
module.exports.GET = async function(req, res) {
send(res, 200, {})
}
// all routes are sorted by this property - the higher numbers are matched first.
// kind of like a z-index for your routes.
// note that equal priority will just sort based on the fs in the case of a collision, which is not guaranteed order on OSX/Linux
module.exports.priority = -1
custom path
// routes/whatever.js
module.exports.GET = async function(req, res) {
send(res, 200, {})
}
// exposing a "path" will override the fs-generated one.
// This is nice if you wanted to avoid making a really deep tree for a one-off path (like for oauth callbacks)
// or if you just want to avoid putting `:` in your file/folder names or something
module.exports.path = '/foo/bar'
index routes
// routes/index.js
module.exports.GET = async function(req, res) {
return 'hello!'
}
// The above route would be reachable at / and /index.
// This works for deep paths (/thing/index.js maps to /thing and /thing/index)
// and even for params (/thing/:param/index.js maps to /thing/* and /thing/*/index).
filter routes
// index.js
const { send } = require('micro')
// set up config to filter only paths including `foo`
const config = {filter: f => f.indexOf('foo') !== -1}
// pass config to `fs-router` as optional second paramater
let match = require('fs-router')(__dirname + '/routes', config)
module.exports = async function(req, res) {
let matched = match(req)
if (matched) return await matched(req, res)
send(res, 404, { error: 'Not found' })
}
The above usage assumes you have a folder called routes
next to the index.js
file, that looks something like this:
routes/
├── foo
│ ├── index.js
│ └── thing.js
└── bar
├── index.js
├── foo.js
└── thing.js
the above tree would generate the following routes:
/foo
/foo/thing
/bar/foo
Multiple file extensions
// index.js
const { send } = require('micro')
// set up the config to both include .js and .ts files.
const config = {ext: ['.js', '.ts']}
// pass config to `fs-router` as optional second paramater
let match = require('fs-router')(__dirname + '/routes', config)
module.exports = async function(req, res) {
let matched = match(req)
if (matched) return await matched(req, res)
send(res, 404, { error: 'Not found' })
}