wouter

🥢 A minimalist-friendly ~1.5KB routing for React and Preact. Nothing else but HOOKS.

Programming language: JavaScript

Tags: Code Design     Router    

README

wouter is a tiny router for modern React and Preact apps that relies on Hooks. A router you wanted so bad in your project!

Features

• Zero dependency, only 1.36 KB gzipped vs 11KB React Router.
• Supports both React and Preact! Read "Preact support" section for more details.
• No top-level <Router /> component, it is fully optional.
• Mimics React Router's best practices by providing familiar Route, Link, Switch and Redirect components.
• Has hook-based API for more granular control over routing (like animations): useLocation, useRoute and useRouter.

developers :sparkling_heart: wouter

... I love Wouter. It’s tiny, fully embraces hooks, and has an intuitive and barebones API. I can accomplish everything I could with react-router with Wouter, and it just feels more minimalist while not being inconvenient.

Matt Miller, An exhaustive React ecosystem for 2020

Wouter provides a simple API that many developers and library authors appreciate. Some notable projects that use wouter: arcade.design (React UI kit), fre, react-three-fiber, ssgl-doom-launcher, Ziro App and many more.

Table of Contents

• Getting Started
• API
  • Hooks
  • useRoute
  • useLocation
  • useRouter
  • Components
  • <Route />
  • <Link />
  • <Switch />
  • <Redirect />
  • <Router />
    • Matching Dynamic Segments
    • Using a path-to-regexp-based matcher
• FAQ and How-to's
  • Base path
  • Default route
  • Active links
  • Nested routes
  • Multipath routes
  • TypeScript support
  • Using with Preact
  • Server-side Rendering (SSR)
  • Routing in less than 400B

Getting Started

Check out this demo app below in order to get started:

import { Link, Route } from "wouter";

const App = () => (
  <div>
    <Link href="/users/1">
      <a className="link">Profile</a>
    </Link>

    <Route path="/about">About Us</Route>
    <Route path="/users/:name">
      {(params) => <div>Hello, {params.name}!</div>}
    </Route>
    <Route path="/inbox" component={InboxPage} />
  </div>
);

Supporting IE11 and obsolete platforms

This library uses features like destructuring assignment and const/let declarations and doesn't ship with ES5 transpiled sources. If you aim to support browsers like IE11 and below → make sure you run Babel over your node_modules

In addition, Event is also used. To be able to run successfully on IE browser, a polyfill is required.

Wouter API

Wouter comes with two kinds of APIs: low-level React Hooks API and more traditional component-based API similar to React Router's one.

You are free to choose whatever works for you: use hooks when you want to keep your app as small as possible or you want to build custom routing components; or if you're building a traditional app with pages and navigation — components might come in handy.

Check out also FAQ and Code Recipes for more advanced things like active links, default routes etc.

The list of methods available

Hooks API:

• useRoute — shows whether or not current page matches the pattern provided.
• useLocation — allows to manipulate current browser location, a tiny wrapper around the History API.
• useRouter — returns a global router object that holds the configuration. Only use it if you want to customize the routing.

Component API:

• <Route /> — conditionally renders a component based on a pattern.
• <Link /> — wraps <a>, allows to perfom a navigation.
• <Switch /> — exclusive routing, only renders the first matched route.
• <Redirect /> — when rendered, performs an immediate navigation.
• <Router /> — an optional top-level component for advanced routing configuration.

Hooks API

useRoute: the power of HOOKS!

Hooks make creating custom interactions such as route transitions or accessing router directly easier. You can check if a particular route matches the current location by using a useRoute hook:

import { useRoute } from "wouter";
import { Transition } from "react-transition-group";

const AnimatedRoute = () => {
  // `match` is boolean
  const [match, params] = useRoute("/users/:id");

  return <Transition in={match}>Hi, this is: {params.id}</Transition>;
};

useLocation hook: working with the history

The low-level navigation in wouter is powered by the useLocation hook, which is basically a wrapper around the native browser location object. The hook rerenders when the location changes and you can also perform a navigation with it, this is very similar to how you work with values returned from the useState hook:

import { useLocation } from "wouter";

const CurrentLocation = () => {
  const [location, setLocation] = useLocation();

  return (
    <div>
      {`The current page is: ${location}`}
      <a onClick={() => setLocation("/somewhere")}>Click to update</a>
    </div>
  );
};

All the components including the useRoute rely on useLocation hook, so normally you only need the hook to perform the navigation using a second value setLocation. You can check out the source code of the Redirect component as a reference.

Customizing the location hook

By default, wouter uses useLocation hook that reacts to pushState and replaceState navigation and observes the current pathname including the leading slash e.g. /app/users.

If you do need a custom history observer, for example, for hash-based routing, you can implement your own hook and customize it in a <Router /> component.

As an exercise, let's implement a simple location hook that listens to hash changes:

import { useState, useEffect } from "react";
import { Router, Route } from "wouter";

// returns the current hash location in a normalized form
// (excluding the leading '#' symbol)
const currentLocation = () => {
  return window.location.hash.replace(/^#/, "") || "/";
};

const navigate = (to) => (window.location.hash = to);

const useHashLocation = () => {
  const [loc, setLoc] = useState(currentLocation());

  useEffect(() => {
    // this function is called whenever the hash changes
    const handler = () => setLoc(currentLocation());

    // subscribe to hash changes
    window.addEventListener("hashchange", handler);
    return () => window.removeEventListener("hashchange", handler);
  }, []);

  return [loc, navigate];
};

const App = () => (
  <Router hook={useHashLocation}>
    <Route path="/about" component={About} />
    ...
  </Router>
);

▶ Demo Sandbox: hash-based routing

useRouter: accessing the router object

If you're building an advanced integration, for example custom location hook, you might want to get access to the global router object. The router is a simple object that holds current matcher function and a custom location hook function.

Normally, router is constructed internally on demand, but it can also be customized via a top-level Router component (see the section above). The useRouter hook simply returns a current router object:

import { useRouter } from "wouter";
import useLocation from "wouter/use-location";

const Custom = () => {
  const router = useRouter();

  // router.hook is useLocation by default

  // you can also use router as a mediator object
  // and store arbitrary data on it:
  router.lastTransition = { path: "..." };
};

Component API

<Route path={pattern} />

Route represents a piece of the app that is rendered conditionally based on a pattern. Pattern is a string, which may contain special characters to describe dynamic segments, see Matching Dynamic Segments section below for details.

The library provides multiple ways to declare a route's body:

import { Route } from "wouter";

// simple form
<Route path="/home"><Home /></Route>

// render-prop style
<Route path="/users/:id">
  {params => <UserPage id={params.id} />}
</Route>

// the `params` prop will be passed down to <Orders />
<Route path="/orders/:status" component={Orders} />

<Link href={path} />

Link component renders an <a /> element that, when clicked, performs a navigation. You can customize the link appearance by providing your own component or a link element as children:

import { Link } from "wouter"

// All of these will produce the same html:
// <a href="/foo" class="active">Hello!</a>

// lazy form: `a` element is constructed around children
<Link href="/foo" className="active">Hello!</Link>

// when using your own component or jsx the `href` prop
// will be passed down to an element
<Link href="/foo"><a className="active">Hello!</a></Link>
<Link href="/foo"><A>Hello!</A></Link>

If you wrap a custom component with Link, wouter won't install event listeners so make sure the component handles onClick and href props properly:

import { Link } from "wouter";

const MyButton = (props) => {
  // it is recommended to use <a>'s when possible (they play nicely with SSR and are SEO-friendly),
  // but wouter's Links should work with almost anything, as long as the `onClick` is handled.
  return (
    <div title={props.href}>
      <button onClick={props.onClick}>Home</button>
    </div>
  );
};

// in your app
<Link href="/home">
  <MyButton />
</Link>;

<Switch />

There are cases when you want to have an exclusive routing: to make sure that only one route is rendered at the time, even if the routes have patterns that overlap. That's what Switch does: it only renders the first matching route.

import { Route, Switch } from "wouter";

<Switch>
  <Route path="/orders/all" component={AllOrders} />
  <Route path="/orders/:status" component={Orders} />
</Switch>;

Check out FAQ and Code Recipes section for more advanced use of Switch.

<Redirect to={path} />

When mounted performs a redirect to a path provided. Uses useLocation hook internally to trigger the navigation inside of a useEffect block.

If you need more advanced logic for navigation, for example, to trigger the redirect inside of an event handler, consider using useLocation hook instead:

import { useLocation } from "wouter";

const [location, setLocation] = useLocation();

fetchOrders().then((orders) => {
  setOrders(orders);
  setLocation("/app/orders");
});

<Router hook={hook} matcher={matchFn} base={basepath} />

Unlike React Router, routes in wouter don't have to be wrapped in a top-level component. An internal router object will be constructed on demand, so you can start writing your app without polluting it with a cascade of top-level providers. There are cases however, when the routing behaviour needs to be customized.

These cases include hash-based routing, basepath support, custom matcher function etc.

A router is a simple object that holds the routing configuration options. You can always obtain this object using a useRouter hook. The list of currently available options:

• hook: () => [location: string, setLocation: fn] — is a React Hook function that subscribes to location changes. It returns a pair of current location string e.g. /app/users and a setLocation function for navigation. You can use this hook from any component of your app by calling useLocation() hook.

Read more → Customizing the location hook.

• matcher: (pattern: string, path: string) => [match: boolean, params: object] — a custom function used for matching the current location against the user-defined patterns like /app/users/:id. Should return a match result and an hash of extracted parameters. It should return [false, null] when there is no match.

• base: string — an optional setting that allows to specify a base path, such as /app. All application routes will be relative to that path. Prefixing a route with ~ will make it absolute, bypassing the base path.

Matching Dynamic Segments

Just like in React Router, you can make dynamic matches either with Route component or useRoute hook. useRoute returns a second parameter which is a hash of all dynamic segments matched. Similarily, the Route component passes these parameters down to its children via a function prop.

import { useRoute } from "wouter";

// /users/alex => [true, { name: "alex "}]
// /anything   => [false, null]
const [match, params] = useRoute("/users/:name");

// or with Route component
<Route path="/users/:name">
  {(params) => {
    /* { name: "alex" } */
  }}
</Route>;

wouter implements a limited subset of path-to-regexp package used by React Router or Express, and it supports the following patterns:

• Named dynamic segments: /users/:foo.
• Dynamic segments with modifiers: /foo/:bar*, /foo/baz? or /foo/bar+.

The library was designed to be as small as possible, so most of the additional matching features were left out (see this issue for more info).

Using a path-to-regexp-based matcher

The <Router /> component accepts an optional prop called matcher which allows to customize how a path is matched against the pattern. By default, a built-in matcher function is used, which implements basic functionality such as wildcard parameters (see above).

However, if you do need to have more advanced functionality, you can specify your own matcher which should look like:

/*
 * accepts a pattern and a path as strings, should return a pair of values:
 * [success, params]
 */

// returns [false, null] when there is no match
matcher("/users", "/") 

// [true, { id: "101" }]
matcher("/users/:id", "/users/101") 

Most of the packages for parsing route patterns work with regular expressions (see path-to-regexp or a super-tiny alternative regexparam), so to make it easier for you wouter provides a factory function for transforming a regexp-based pattern builder into a matcher. It also makes sure that the expensive transform operation isn't called on each render by utilizing a simple cache.

import { Router } from "wouter";

import makeCachedMatcher from "wouter/matcher";

/*
 * This function specifies how strings like /app/:users/:items* are
 * transformed into regular expressions.
 *
 * Note: it is just a wrapper around `pathToRegexp`, which uses a
 * slighly different convetion of returning the array of keys.
 *
 * @param {string} path — a path like "/:foo/:bar"
 * @return {{ keys: [], regexp: RegExp }}
 */
const convertPathToRegexp = (path) => {
  let keys = [];

  // we use original pathToRegexp package here with keys
  const regexp = pathToRegexp(path, keys, { strict: true });
  return { keys, regexp };
};

const customMatcher = makeCachedMatcher(convertPathToRegexp);

function App() {
  return (
    <Router matcher={customMatcher}>
      {/* at the moment wouter doesn't support inline regexps, but path-to-regexp does! */}
      <Route path="/(resumes|cover-letters)/:id" component={Dashboard} />
    </Router>
  )
}

▶ Demo Sandbox

FAQ and Code Recipes

I deploy my app to the subfolder. Can I specify a base path?

You can! Wrap your app with <Router base="/app" /> component and that should do the trick:

import { Router, Route, Link } from "wouter";

const App = () => (
  <Router base="/app">
    {/* the link's href attribute will be "/app/users" */}
    <Link href="/users">Users</Link>

    <Route path="/users">The current path is /app/users!</Route>
  </Router>
);

Note: the base path feature is only supported by the default pushState hook. If you're implementing your own location hook, you'll need to add base path support yourself.

How do I make a default route?

One of the common patterns in application routing is having a default route that will be shown as a fallback, in case no other route matches (for example, if you need to render 404 message). In wouter this can easily be done as a combination of <Switch /> component and a default route:

import { Switch, Route } from "wouter";

<Switch>
  <Route path="/about">...</Route>
  <Route>404, Not Found!</Route>
</Switch>;

Note: the order of switch children matters, default route should always come last. If you want to have access to the matched segment of the path you can use :param*:

<Switch>
  <Route path="/users">...</Route>

  {/* will match anything that starts with /users/, e.g. /users/foo, /users/1/edit etc. */}
  <Route path="/users/:rest*">...</Route>

  {/* will match everything else */}
  <Route path="/:rest*">
    {(params) => `404, Sorry the page ${params.rest} does not exist!`}
  </Route>
</Switch>

▶ Demo Sandbox

How do I make a link active for the current route?

There are cases when you need to highlight an active link, for example, in the navigation bar. While this functionality isn't provided out-of-the-box, you can easily write your own <Link /> wrapper and detect if the path is active by using the useRoute hook. The useRoute(pattern) hook returns a pair of [match, params], where match is a boolean value that tells if the pattern matches current location:

const [isActive] = useRoute(props.href);

return (
  <Link {...props}>
    <a className={isActive ? "active" : ""}>{props.children}</a>
  </Link>
);

▶ Demo Sandbox

Are strict routes supported?

If a trailing slash is important for your app's routing, you could specify a custom matcher that implements the strict option support.

import makeMatcher from "wouter/matcher";
import { pathToRegexp } from "path-to-regexp";

const customMatcher = makeMatcher((path) => {
  let keys = [];
  const regexp = pathToRegexp(path, keys, { strict: true });
  return { keys, regexp };
});

const App = () => (
  <Router matcher={customMatcher}>
    <Route path="/foo">...</Route>
    <Route path="/foo/">...</Route>
  </Router>
);

▶ Demo Sandbox

Are relative routes and links supported?

Unlike React Router, there is no first-class support for route nesting. However, thanks to the base path support, you can easily implement a nesting router yourself!

const NestedRoutes = (props) => {
  const router = useRouter();
  const [parentLocation] = useLocation();

  const nestedBase = `${router.base}${props.base}`;

  // don't render anything outside of the scope
  if (!parentLocation.startsWith(nestedBase)) return null;

  // we need key to make sure the router will remount when base changed
  return (
    <Router base={nestedBase} key={nestedBase}>
      {props.children}
    </Router>
  );
};

const App = () => (
  <Router base="/app">
    <NestedRoutes base="/dashboard">
      {/* the real url is /app/dashboard/users */}
      <Link to="/users" />
      <Route path="/users" />
    </NestedRoutes>
  </Router>
);

▶ Demo Sandbox

Is it possible to match an array of paths?

While wouter doesn't currently support multipath routes, you can achieve that in your app by specifying a custom matcher function:

import makeMatcher from "wouter/matcher";

const defaultMatcher = makeMatcher();

/*
 * A custom routing matcher function that supports multipath routes
 */
const multipathMatcher = (patterns, path) => {
  for (let pattern of [patterns].flat()) {
    const [match, params] = defaultMatcher(pattern, path);
    if (match) return [match, params];
  }

  return [false, null];
};

const App = () => (
  <Router matcher={multipathMatcher}>
    <Route path={["/app", "/home"]}>...</Route>
  </Router>
);

▶ Demo Sandbox

Can I use wouter in my TypeScript project?

Yes! Although the project isn't written in TypeScript, the type definition files are bundled with the package.

Preact support?

Preact exports are available through a separate package named wouter-preact (or within the wouter/preact namespace, however this method isn't recommended as it requires React as a peer dependency):

- import { useRoute, Route, Switch } from "wouter";
+ import { useRoute, Route, Switch } from "wouter-preact";

You might need to ensure you have the latest version of Preact X with support for hooks.

▶ Demo Sandbox

Is there any support for server-side rendering (SSR)?

Yes! In order to render your app on a server, you'll need to tell the router that the current location comes from the request rather than the browser history. In wouter, you can achieve that by replacing the default useLocation hook with a static one:

import { renderToString } from "react-dom/server";
import { Router } from "wouter";

// note: static location has a different import path,
// this helps to keep the wouter source as small as possible
import staticLocationHook from "wouter/static-location";

import App from "./app";

const handleRequest = (req, res) => {
  // The staticLocationHook function creates a hook that always
  // responds with a path provided
  const prerendered = renderToString(
    <Router hook={staticLocationHook(req.path)}>
      <App />
    </Router>
  );

  // respond with prerendered html
};

Make sure you replace the static hook with the real one when you hydrate your app on a client.

If you want to be able to detect redirects you can provide the record option:

import { renderToString } from "react-dom/server";
import { Router } from "wouter";
import staticLocationHook from "wouter/static-location";

import App from "./app";

const handleRequest = (req, res) => {
  const location = staticLocationHook(req.path, { record: true });
  const prerendered = renderToString(
    <Router hook={location}>
      <App />
    </Router>
  );

  // location.history is an array matching the history a
  // user's browser would capture after loading the page

  const finalPage = locationHook.history.slice(-1)[0];
  if (finalPage !== req.path) {
    // perform redirect
  }
};

1KB is too much, I can't afford it!

We've got some great news for you! If you're a minimalist bundle-size nomad and you need a damn simple routing in your app, you can just use the useLocation hook which is only 400 bytes gzipped and manually match the current location with it:

import useLocation from "wouter/use-location";

const UsersRoute = () => {
  const [location] = useLocation();

  if (location !== "/users") return null;

  // render the route
};

Wouter's motto is "Minimalist-friendly".

Acknowledgements

Wouter illustrations and logos were made by Katya Simacheva and Katya Vakulenko.