letterpress

@johnhenry/letterpress is a routing library built around tagged template strings: a route’s method, path, and even response body can be written as one literal template rather than assembled from config objects. It doesn’t run a server itself — pair it with leserve’s serve() (or any server of your choice) to actually listen for requests.

Previously published as leroute, last unscoped version 0.0.1. Now @johnhenry/letterpress, restarting at 0.0.0.

Letterpress works great with leserve — this package carries an explicit devDependency on @johnhenry/leserve, and every usage example below runs its router through leserve’s serve().

Install

npm install @johnhenry/letterpress

Quick example

import serve from "@johnhenry/leserve";
import { createRouter, createRoute } from "@johnhenry/letterpress";

const router = createRouter();

// A route defined as one tagged template: method, path, and response body.
router.endpoint`GET /``
<!DOCTYPE html>
<html lang="en">
  <body>
    <h1>Welcome to Letterpress</h1>
    <p>The current time is: ${() => new Date().toISOString()}</p>
  </body>
</html>
`;

// Route parameters are just template placeholders in the path.
router.endpoint`GET /user/:id``
<!DOCTYPE html>
<html lang="en">
  <body>
    <h1>User Profile</h1>
    <p>User ID: ${(_, { params }) => params.id}</p>
  </body>
</html>
`;

serve({ port: 8080 }, router);

A route handler doesn’t have to be a template — a plain function works too, for cases better expressed as code than markup:

router.endpoint`GET /api/data`(async (request) => {
  const data = { message: "Hello, World!", timestamp: new Date().toISOString() };
  return new Response(JSON.stringify(data), {
    headers: { "Content-Type": "application/json" },
  });
});

Route patterns can also match on headers, not just method and path:

router.endpoint`GET /protected [Authorization: Bearer *]``
HTTP/1.1 200 OK
Content-Type: text/plain

This is a protected resource
`;

And a router accepts a custom errorHandler:

const errorHandler = (error, request) => {
  console.error("Error:", error);
  return new Response("An error occurred", { status: 500 });
};

serve({ port: 8080 }, router, { errorHandler });

What’s in it

createRouter / createRoute — build a router and individual route handlers.
HTTPExpression — a tagged-template function for matching requests against a method/path/header pattern, independent of routing.
createRequest / createResponse — build Request/Response objects from raw HTTP-message-shaped template literals.
createFSRouter — build a Router from a filesystem-based route directory.
deconstruct / cook — the lower-level tagged-template primitives the rest of the library is built on.

See API for the full reference.

License

MIT

Source

github.com/johnhenry/letterpress