ThingRouter

A small router package, written in typesript. The goal of this router is to simply call a function if a path such as /author/:author/article/:id matches.

The primary reason this was made, is to create a simple system for finding an 'entity' or 'model' based on its url.

This package does not aim to replace routers commonly found in server-side frameworks, but such a router could be built with this library.

This package uses the following two dependencies matching express-style url patterns:

• path-to-regexp
• path-match

Installation

npm i thing-router

Usage

Setting up a route:

import ThingRouter from 'thing-router';

const thingRouter = new ThingRouter();

type ArticleParams = {
  id: string
}
type Article = {
  id: number,
  title: string
};

thingRouter.add(
  '/article/:id',
  (params: ArticleParams): Article => {

    return {
      id: parseInt(params.id, 10),
      title: 'Article id: '  + params.id,
    };
  }
);

The above example registers a new route /article/:id. This callback should find an article associated with this url.

It's recommended to specify the types of both the parameters you're expecting, and the type that's being returned for a matched path.

Matching the route

const article = thingRouter('/article/5');

If the path could not be matched in the router, or if the callback returned null, a NotFoundError will be thrown.

Structuring code

If you're setting up many routes, it might be beneficial to define the callback function in another file, simply pass in the imported function.

thingRouter.add('/article/:id', articleFinder);
thingRouter.add('/author/:id', authorFinder);
thingRouter.add('/category/:id', categoryFinder);

This will make long lists more readable. It's also possible to pass all the routes via the constructor. This has the same effect:

const thingRouter = new ThingRouter([
  ['/article/:id',  articleFinder],
  ['/author/:id',   authorFinder],
  ['/category/:id', categoryFinder],
]);

Ensuring that the you're getting the right kind of thing.

Suppose you expect to receive an 'author' from the router, but the user specified a url to an 'article', you can let the router check this.

To do this, you must specifiy a 'kind' argument when setting up the route. This is the optional 3rd argument to 'add()':

thingRouter.add(
  '/author/:name', //path
  authorFinder, // callback
  'author', // kind
);

Now we're trying to fetch an author, but the path leads to a category instead:

const author = thingRouter('/category/5', 'author');

The above will thow a WrongKindError.

If you are using json-schema a suggested value for the kind parameter could be the $id attribute.