ROUTETS
Vanilla filesystem-based routing for Deno.
routets is a Handler generator that performs filesystem-based routing.
No other stuff. That's all. I was always tired of fullstack frameworks such as Fresh or Aleph.js, because of the tightly coupled design that forces users to be on the rails. So I ended up making this stupid-simple solution, which is aimed to be:
- No magic and no blackbox
- Small size and less dependency
- No squatted pathnames like
/_appor/_404 - No lock-in to a specific JSX implementation
- No lock-in to a specific architecture; MPA or SPA, SSR or CSR, etc.
So, routets is deliberately less-featured. It just provides a basic building block for writing web servers in Deno, leveraging Create Your Own™ style of experience.
Basic Usage
Create a file with the filename being <your-route-name>.route.ts, say ./greet.route.ts here and the content is like this:
import Route from "https://lib.deno.dev/x/routets@v2/Route.ts"
export default new Route(async () => {
return new Response("Hello, World!")
})routets comes with a built-in CLI. During development, you can use this and serve your routes immediately:
$ deno install -Af https://lib.deno.dev/x/routets@v2/routets.ts
$ routets # or `routets somewhere` to serve `somewhere/greet.route.ts` at `/greet`
Listening on http://localhost:8000/And you'll see “Hello, World!” at http://localhost:8000/greet.
Alternatively, of course you can create your own script:
import Router from "https://lib.deno.dev/x/routets@v2/Router.ts"
import { serve } from "https://deno.land/std@0.192.0/http/server.ts"
await serve(await new Router({ root: import.meta.resolve("./.") }))Advanced Usage
Dynamic Routes
routets supports dynamic routes by URL Pattern API. Please refer to the MDN documentation for the syntax and examples.
Matched parts of the pathname will be passed to the second argument of the handler. For example, when you have :dynamic.route.ts with the content being:
import Route from "https://lib.deno.dev/x/routets@v2/Route.ts"
export default new Route(async ({ slugs }) => {
return new Response(JSON.stringify(slugs), { headers: { "Content-Type": "application/json" } })
})Accessing /route will show you {"dynamic":"route"}.
Route Precedence
Once you have started using dynamic routes, you may notice it is unclear which route will be matched when multiple dynamic routes are valid for the requested pathname. For example, if you have a file named greet.route.ts and another file named *.route.ts, which one will be matched when you access /greet?
By default, routets doesn't do anything smart, and just performs codepoint-wise lexicographic ordering. So, in the above example, *.route.ts will be matched first, as * precedes g in Unicode. If you want to change this behavior, just named-export a number as precedence from each route:
// in `*.route.ts`
export const precedence = 0// in `greet.route.ts`
export const precedence = 9Routes with greater precedences are matched first. Think of it as z-index in CSS. So, this time greet.route.ts will be matched first.
If precedence is not exported, it implies 0.
Route Fallthrough
If a route returns nothing (namely undefined), then it fallthroughs to the next matching route.
Extending Route
If you want to insert middlewares before/after an execution of handlers, you can extend the Route class as usual in TypeScript.
To exercise this, here we add support for returning a React element from handlers!
import Route from "https://lib.deno.dev/x/routets@v2/Route.ts"
import { renderToReadableStream } from "https://esm.sh/react-dom@18.2.0/server"
import { isValidElement, ReactElement, Suspense } from "https://esm.sh/react@18.2.0"
class RouteReact extends Route {
constructor(handler: Route.Handler<ReactElement<unknown>>) {
super(async context => {
const response = await handler(context)
return new Response(
await renderToReadableStream(
<html>
<body>
<Suspense fallback={<p>Loading...</p>}>{response}</Suspense>
</body>
</html>,
),
{ headers: { "Content-Type": "text/html" } },
)
})
}
}
export default RouteReactAnd don't forget to add following options to your deno.jsonc:
{
"compilerOptions": {
"jsx": "react-jsx",
"jsxImportSource": "https://esm.sh/react@18.2.0"
}
}That's it! You can now create a route with it:
import RouteReact from "./RouteReact.ts"
import { delay } from "https://deno.land/std@0.192.0/async/delay.ts"
let done = false
const Component = () => {
if (!done) {
throw delay(3000).then(() => (done = true))
} else {
done = false
return <b>Hello, World!</b>
}
}
export default new RouteReact(async () => {
return <Component />
})In a browser, this will show you “Loading…” for 3 seconds, and then “Hello, World!”.
Suffix Restrictions
Changing the route filename suffix (route by default) is possible by --suffix when using the CLI and by suffix option when using the Router constructor. Although, there are some restrictions on the shape of suffixes:
- Cannot be empty
- Cannot contain slashes
- Cannot start or end with dots
These are by design and will never be lifted.
Deploying to Deno Deploy
routets uses dynamic imports to discover routes. This works well locally, but can be a problem if you want to get it to work with environments that don't support dynamic imports, such as Deno Deploy.
For this use case, by default the routets CLI and the Router constructor do generate a server module serve.gen.ts that statically imports routes. This module can directly be used as the entrypoint for Deno Deploy.
You can disable this behavior by --no-write option when using the CLI and by write option when using the Router constructor.
Difference from fsrouter
There exists a similar package fsrouter which has quite the same UX overall, but slightly different in:
- Suffix namespacing.
routetsuses namespaced filenames e.g.greet.route.ts, whilefsrouteris justgreet.ts. - Dynamic routing syntax.
routetsuses URL Pattern API e.g.:id.route.ts, whilefsrouteruses the bracket syntax e.g.[id].ts. Also,routetsdoesn't support typed dynamic routes. - JavaScript file extensions.
routetsdoesn't allowjsorjsx, whilefsrouterdoes.
Semver Policy
Only the default exports are public APIs and remain stable throughout minor version bumps. Named exports should be considered private and unstable. Any single release may randomly contain breaking changes to named exports, so users should avoid using them where possible.