@olefjaerestad/router v0.0.4

Router

Lightweight client side JavaScript router to run certain code at certain URL routes.

Installation

npm i @olefjaerestad/router

API/examples

TODO:

Create a router

import { Router } from '@olefjaerestad/router';

const router = new Router();

Run callback function at specific route

/* Log req when route is '/home'. */
router.get('/home', (req) => console.log(req));

/* Do additional logging when route is '/home'. Will _not_ overwrite previously registered callbacks for the same route. */
router.get('/home', (req) => console.log('Another callback at /home'));

/* Within non-arrow callbacks, this = the Router instance. */
router.get('/about', function(req) {
	console.log(this); // Router
});

Note: You can call Router.get on the same route as many times as you need.

Fallback route

You might want some code to run when no routes are matched. You can do this by adding a '/404' route.

/* This route will trigger when no routes are matched. */
router.get('/404', (req) => console.log(req));

Note: This route will trigger both if no routes are matched or if the current route is '/404'.

Route params

Routes don't have to be static. Just like in Express, you can use route parameters. For all possible syntaxes, see Route parameters in Express.

router.get('/blog/:slug/:id/:test', (req) => {
	console.log(req.params.slug);
	console.log(req.params.id);
	console.log(req.params.test);
});

Given the code above and a route of /blog/my-post/123/hello, the following will be logged:

my-post
123
hello

Delete route

/* Stop running callback functions for '/home' route. */
router.delete('/home');

Middleware

In addition to a callback function, Router.get() also supports middleware. Much like Express middleware, middleware are basically additional callback functions that can alter the req object or stop the execution of further route middleware and the route callback.

Alter the req object:

const reqMiddleware = (req) => myFunc() ? req.foo = 'bar' ? null;

/* req.foo will be 'bar' or undefined, depending on the result of myFunc(). */
router.get('/home', reqMiddleware, (req) => console.log(req.foo));

Stop the execution of further route middleware and the route callback:

const authMiddleware = (req) => isLoggedIn();

/* If authMiddleware() === false, req won't be logged even if route is '/home'. */
router.get('/home', authMiddleware, (req) => console.log(req));

Note: Middleware will be ran in the order they are passed to Router.get(), from left to right.

Note 2: Returning false in a middleware will only affect the callback/middleware that were registered in the same Router.get() call as it. Modifying req however, will affect callbacks/middleware across all Router.get() calls for that route.

Async middleware and callbacks

Middleware and callbacks can also be async, which could be useful when doing things like network requests, authentication, etc.

const authMiddleware = async (req) => await isLoggedIn();

/* If authMiddleware() === false, callback won't run even if route is '/home'. */
router.get('/home', authMiddleware, async (req) => {
	const result = await getPromise();
	console.log(result);
});

Note: Async middleware must resolve (be completed) before the next middleware/callback starts executing.

The request object

You might've already seen the req object being passed to middleware and callbacks. This is an object containing information about your current route. The object has the the following properties:

• req.route - A string containing the current route.
• req.params - An object with key-value pairs containing the route parameters. Note that number params (e.g. IDs) are converted to numbers. All others params are strings.

Navigating to route

router.navigate('/home');

Router instances also add event listeners to the window and document, so that [router-href] elements and browser back/forwards buttons can be used to trigger routes. Router.removeEventListeners() can be used to cleanup (i.e. remove) these event listeners.

<!-- Click to navigate to the '/about' route. -->
<a href="" router-href="/about" title="See info about me">About</a>

Note: If router-href is empty, the element will be treated as a normal link.

Note 2: router-href can be used on any element, not just links. Be aware of accessibility concerns if doing this.

Typescript

The package supports typings through .d.ts files. The following named exports are exported from the package:

• Router: class that creates a router.
• IRouterCallback: interface for the router middleware and callbacks.

Browser support

TODO: Update table below.

Browser support is mainly affected by use of the following:

• Classes
• async await syntax

Developing

npm run dev

Then just start editing the code in /src. If using an editor with good TypeScript support (e.g. VS Code), any errors will be inlined in the code as well.

Note: Dev produces no output files.

Testing

Integration testing:

npm run test:browsers

This will open a separate window where you can choose which browser to test in. Note that browsers are limited to browsers that are installed on your system and supported by Cypress.

Building

npm run build

Note: Build will fail and report if there are errors.

Publishing

Publish to npm:

npm run publish:npm

Note: Requires being logged in to npm locally.