Prerequisites

• svelte >= 5.0.0

Install

pnpm add @dvcol/svelte-simple-router

Getting Started

The minimal setup requires a RouterView component and a list of routes.

The RouterView component will render the component associated with the current route in place.

You can find a complete example in the demo app.

<script lang="ts">
  import { RouterView } from '@dvcol/svelte-simple-router/components';

  import type { Route, RouterOptions } from '@dvcol/svelte-simple-router/models';
  
  import HelloComponent from '~/components/hello/HelloComponent.svelte';
  import GoodbyeComponent from '~/components/goodbye/GoodbyeComponent.svelte';

  const RouteName = {
    Hello: 'hello',
    Goodbye: 'goodbye',
    Home: 'home',
    Any: 'any',
  } as const;

  type RouteNames = (typeof RouteName)[keyof typeof RouteName];

  export const routes: Readonly<Route<RouteNames>[]> = [
    {
      name: RouteName.Home,
      path: '/',
      redirect: {
        name: RouteName.Hello,
      },
    },
    {
      name: RouteName.Hello,
      path: `/${RouteName.Hello}`,
      component: HelloComponent
    },
    {
      name: RouteName.Goodbye,
      path: `/${RouteName.Goodbye}`,
      component: GoodbyeComponent
    },
    {
      name: RouteName.Any,
      path: '*',
      redirect: {
        name: RouteName.Hello,
      },
    },
  ] as const;

  export const options: RouterOptions<RouteNames> = {
    routes,
  } as const;
  
</script>

<RouterView {options} />

Advanced Usage

• Router Context
• Debuggers
• Nested routes
• Router transition
  • Svelte transition
  • View Transition API
• Dom actions
  • Link action
  • Active action
• Programmatic navigation
  • Hooks
  • Router instance
  • Outside component tree
• Dynamic routes
• Guards and listeners
  • Navigation listeners
  • Loading Listeners
• Lazy routing
• Routes
• Router

Router Context

The RouterContext component injects the router instance into the component tree.

It can be used to share a router instance between RouterView components without the need to pass it down as a prop.

<script lang="ts">
  import { RouterContext } from '@dvcol/svelte-simple-router/components';
  import { RouterView } from '@dvcol/svelte-simple-router/components';
</script>

<RouterContext>
  <!--  children  -->
</RouterContext>

Debuggers

The RouterDebugger and RouteDugger component will display the current route and router state.

It can be used to debug the router configuration and the current route.

It requires to be placed inside a RouterView or RouterContext component.

<script lang="ts">
  import { RouterDebugger, RouteDebugger } from '@dvcol/svelte-simple-router/components/debug';
  import { RouterView } from '@dvcol/svelte-simple-router/components';
</script>

<RouterView>
  <RouterDebugger />
  <RouteDebugger />
</RouterView>

Nested routes

The RouterView component can be nested under another RouterView or RouterContext component.

Named RouterView components can be used to render different components on the same route.

Each RouterView grabs the router context from the nearest RouterContext or RouterView component.

Note: Sibling RouterView or RouterContext components will instantiate a new router instance.

<script lang="ts">
  import { RouterView } from '@dvcol/svelte-simple-router/components';
  import { RouterContext } from '@dvcol/svelte-simple-router/components';

  import type { Route, RouterOptions } from '@dvcol/svelte-simple-router/models';
  
  import ParentComponent from '~/components/hello/ParentComponent.svelte';
  import ChildComponent from '~/components/goodbye/ChildComponent.svelte';

  const RouteName = {
    Parent: 'parent',
    Child: 'child',
  } as const;

  type RouteNames = (typeof RouteName)[keyof typeof RouteName];

  export const routes: Readonly<Route<RouteNames>[]> = [
    {
      name: RouteName.Parent,
      path: `/${RouteName.Parent}`,
      component: ParentComponent
    },
    {
      name: RouteName.Nested,
      path: `/${RouteName.Parent}/${RouteName.Child}`,
      components: {
        default: ParentComponent,
        nested: ChildComponent,
      }
    },
  ] as const;

  export const options: RouterOptions<RouteNames> = {
    routes,
  } as const;

</script>

<RouterContext {options}>
  <RouterView>
    <!--  will render ParentComponent  -->
  </RouterView>
  
  <RouterView name="nested">
    <!--  will only render ChildComponent on /parent/child, and nothing on /parent -->
  </RouterView>
</RouterContext>

Router transition

Svelte transition

The RouterView component can take a transition prop to animate the route transition.

It wraps the route component in a div with optionals in and out transitions.

A default fade/scale transition is provided, but you can pass your own transitions.

Note: By default the first enter transition is ignored, you can change this behavior by setting the skipFirst option to false.

<script lang="ts">
  import { RouterView } from '@dvcol/svelte-simple-router/components';
  import { transition } from '@dvcol/svelte-simple-router/utils';
  
  ...
</script>

<RouterView {transition} {options} />

View Transition API

If you want to use the view-transition API instead, you can pass a viewTransitionName key in the transition prop of the RouterView component.

If viewTransitionName is a string, it will be used as the viewTransitionName, otherwise a unique id will be generated sr-container-<router-id>-<view-id>.

Then, you can use one or a combination of lifecycle hooks like onChange or onStart to trigger transitions.

<script lang="ts">
  import { onChange, onError, onLoaded } from '@dvcol/svelte-simple-router/router';
  
  let resolve: () => void;

  const starTransition = () => {
    const { promise: transition, resolve: end } = Promise.withResolvers<void>();
    resolve = end;

    const { promise: wait, resolve: start } = Promise.withResolvers<void>();
    document.startViewTransition(async () => {
      start();
      await transition;
    });
    return wait;
  };

  onChange(async () => {
    if (resolve) resolve();
    return starTransition();
  });

  onError(() => resolve?.());
  onLoaded(() => resolve?.());
</script>

Dom actions

Link action

The link action intercepts click events on dom elements and triggers a router navigation instead.

The link action will prevent the default behavior and use the router only if the following conditions are met:

• The element is within a router context
• The event is a left click or enter key
• The event does not have a modifier key
• The target is not an external link (for anchor elements)
• The target is not a new tab or window (for anchor elements)

Additionally:

• The action merge data-attributes with the options passed as argument.
• Passed options have precedence over data-attributes.
• If attribute expects a JSON object, it will be parsed.
• If a name or path parameter are provided, they will be used to navigate and href will be ignored.
• Name takes precedence over path.
• If the host is not an anchor element, the role and tabindex attributes will be set.

Note: The action requires the router context to be present in the component tree.

<script lang="ts">
  import { link } from '@dvcol/svelte-simple-router/router';
</script>

<a href="/path/:param?query=value" use:link>simple link</a>
<a href='goodbye' name use:link>named link</a>
<a href='/path/:param' data-query='{"query":"value"}' use:link>link with query</a>
<a href='/path/:param' use:link="{ params: { param: 'value' } }">link with params</a>
<div href='/path/:param' use:link="{ params: { param: 'value' } }">div link</div>
<button href='/path/:param' use:link="{ params: { param: 'value' } }">button link</button>

Active action

The active action adds an active state (class, style or attribute) to an element when the route matches.

Additionally:

• If attached to an anchor element, it will attempt to match the href attribute.
• If path or name options are provided, they will take precedence over the element attributes.
• Name always takes precedence over path.
• When the route un-matches, the original style will be restored.

Note: The action requires the router context to be present in the component tree.

<script lang="ts">
  import { active } from '@dvcol/svelte-simple-router/router';
</script>

<a href="/path" use:active>simple link</a>
<a href="/path" data-name="route-name" use:active>named link</a>
<button :use:active="{ path: '/path' }">button link</button>
<div :use:active="{ name: 'route-name' }">div link</div>

Programmatic navigation

Hooks

• hasRouter & useRouter - Returns the router instance

Must be used within a RouterView or RouterContext.

<script lang="ts">
  import { useRouter } from '@dvcol/svelte-simple-router/router';
  
  const router = useRouter()
</script>

• hasView & useView - Returns the view instance

Must be used within a RouterView.

<script lang="ts">
  import { useView } from '@dvcol/svelte-simple-router/router';
  
  const view = useView()
</script>

• useRoute - Returns the current route, location and the routingstate

Must be used within a RouterView or RouterContext.

<script lang="ts">
  import { useRoute } from '@dvcol/svelte-simple-router/router';
  
  const { route, location, routing } = useRoute()
  
  const reactiveRoute = $derived(route)
  const reactiveLocation = $derived(location)
  const reactiveRoutingState = $derived(routing)
</script>

• useNavigate - Returns utility function to start navigation logic.

Must be used within a RouterView or RouterContext.

<script lang="ts">
  import { useNavigate } from '@dvcol/svelte-simple-router/router';
  
  const { resolve, push, replace, back, forward, go } = useNavigate()
</script>

• beforeEach - Returns a onMount hook that register (and auto-clean) a listener that triggers before each navigation event

Must be used within a RouterView or RouterContext.

<script lang="ts">
  import { beforeEach } from '@dvcol/svelte-simple-router/router';
  
  beforeEach((event) => {
    console.info('before navigation', event);
  })
</script>

• onStart - Returns a onMount hook that register (and auto-clean) a listener that triggers at the start of each navigation event

Must be used within a RouterView or RouterContext.

<script lang="ts">
  import { onStart } from '@dvcol/svelte-simple-router/router';
  
  onStart((event) => {
    console.info('start of navigation', event);
  })
</script>

• onEnd - Returns a onMount hook that register (and auto-clean) a listener that triggers at the end of each navigation event

Must be used within a RouterView or RouterContext.

<script lang="ts">
  import { onEnd } from '@dvcol/svelte-simple-router/router';
  
  onEnd((event) => {
    console.info('end of navigation', event);
  })
</script>

• onChange - Returns a onMount hook that register (and auto-clean) a listener that triggers at the start of a view change.

Must be used within a RouterView.

<script lang="ts">
  import { onChange } from '@dvcol/svelte-simple-router/router';
  
  onChange((event) => {
    console.info('start of view change', event);
  })
</script>

• onLoading - Returns a onMount hook that register (and auto-clean) a listener that triggers when a view start loading an async component.

Must be used within a RouterView.

<script lang="ts">
  import { onLoading } from '@dvcol/svelte-simple-router/router';
  
  onLoading((event) => {
    console.info('loading view', event);
  })
</script>

• onLoaded - Returns a onMount hook that register (and auto-clean) a listener that triggers when a view finish loading a component.

Must be used within a RouterView.

<script lang="ts">
  import { onLoaded } from '@dvcol/svelte-simple-router/router';
  
  onLoaded((event) => {
    console.info('view loaded', event);
  })
</script>

• onError - Returns a onMount hook that register (and auto-clean) a listener that triggers when an error occurs during navigation or view change.

Must be used within a RouterView.

<script lang="ts">
  import { onError, NavigationEvent, ViewChangeEvent } from '@dvcol/svelte-simple-router/router';
  
  onError((err, event) => {
    if (event instanceof NavigationEvent) {
      console.error('Navigation Error', { err, event });
    } else if (event instanceof ViewChangeEvent) {
      console.error('View change error', { err, event });
    } else {
      console.error('Unknown Error', { err, event });
    }
  });
</script>

• onViewError - Returns a onMount hook that register (and auto-clean) a listener that triggers when an error occurs during view change.

Must be used within a RouterView.

<script lang="ts">
  import { onViewError } from '@dvcol/svelte-simple-router/router';
  
  onViewError((err, event) => {
    console.error('View change error', { err, event });
  });
</script>

• onRouterError - Returns a onMount hook that register (and auto-clean) a listener that triggers when an error occurs during navigation.

Must be used within a RouterView or RouterContext.

<script lang="ts">
  import { onRouterError } from '@dvcol/svelte-simple-router/router';
  
  onRouterError((err, event) => {
    console.error('Navigation error', { err, event });
  });
</script>

Router instance

For more complexe usage, you can grab the router instance from the context and call the push or replace methods.

See the router model for more information.

<script lang="ts">
  import { RouterContext } from '@dvcol/svelte-simple-router/components';
  import { RouterView } from '@dvcol/svelte-simple-router/components';
  import { useRouter } from '@dvcol/svelte-simple-router/router';
  
  const router = useRouter();
  
  const onPush = () => {
    router.push({ path: "/route-path" });
  };
  
  const onReplace = () => {
    router.replace({ name: "route-name" });
  };
</script>

Outside component tree

If you need to access the router instance outside of a component, you can instantiate a router instance and pass it to the RouterContext or RouterView component.

import { Router } from '@dvcol/svelte-simple-router/router';

export const router = new Router();

<script lang="ts">
  import { RouterView } from '@dvcol/svelte-simple-router/components';
  
  import { router } from './router';
</script>

<RouterView {router} />

Router navigation support several options:

• name or path to navigate to a named or path route.
• params to pass route parameters.
• query to pass query parameters.
• state to pass an history state object.
• stripQuery to remove current query parameters from the url.
• stripHash to remove the hash from the url (only in path mode).
• stripTrailingHash to remove the trailing hash from the url (only in hash mode).

You can also override the router's navigation options:

• base to set the base path for the router.
• hash to enable hash routing.
• strict to enable strictly match routes (i.e. /path will not match /path/child).
• force to force navigation even if the route is the same.
• caseSensitive to enable case sensitive route names.
• failOnNotFound to throw an error when a route is not found.
• metaAsState to pass the route meta as state when navigating.
• nameAsTitle to set the document title to the route name.
• followGuardRedirects to follow guard redirects.

Dynamic routes

You can dynamically add or remove routes from the router instance.

Note that although the inner route map are reactive, adding or removing routes will not trigger a re-synchronization of the router state.

To force a re-synchronization, you can call the sync method on the router instance.

You can also use the RouteView component to declare routes dynamically. When the component is added to the component tree, the routes will be added to the router instance. When the component is removed from the component tree, the routes will be removed from the router instance.

RouteView can be passed a route object and will add it to the closest router instance. Additionally, if the component/components/redirect are missing, it will try to infer them from the component's children and snippets. When inside a named RouterView, the children will be added to the components object under the name key (provided or discovered through context).

RouteView supports the same error and loading snippets as the RouterView component. In addition, named children can be passed as snippets to the component and will be injected into the components object. If a snippet with the same name as the RouterView is found, the children will be injected into the components object under the default key instead.

Note: Inputs are not reactive, so you will need to un-mout and remount the component to trigger a route update. It is recommended to use the router instance directly if you need to frequently update routes.

<script lang="ts">
  import { RouterView, RouterContext, RouteView} from '@dvcol/svelte-simple-router/components';
  import { toLazyComponent } from '@dvcol/svelte-simple-router/utils';

  import type { PartialRoute } from '@dvcol/svelte-simple-router/models';
  
  import ParentComponent from '~/components/hello/ParentComponent.svelte';
  import ChildComponent from '~/components/goodbye/ChildComponent.svelte';
  
  const LazyComponent = toLazyComponent(() => import('./LazyComponent.svelte'));

  const parent: PartialRoute = {
    name: 'parent',
    path: '/parent',
  };
  
  const child: PartialRoute = {
    name: 'child',
    path: '/parent/child',
  };
  
</script>

<RouterContext {options}>
  <RouterView>
    <RouteView route={parent}>
        <!-- Will render the children in this 'default' RouterView -->
        <ParentComponent />
        
        <!-- Will render this snippet in the 'nested' RouterView -->
        {#snippet nested()}
            <ChildComponent />
        {/snippet}
    </RouteView>
  </RouterView>
  
  <RouterView name="nested">
    <RouteView route={parent}>
        <!-- Will render the children in this 'nested' RouterView, and nothing in the default when  on '/parent/child' -->
        <ChildComponent />
    </RouteView>
    
    <!-- Inline example -->
    <RouteView route={{ path: '/other' }} children={ParentComponent} nested={LazyComponent} />
  </RouterView>
</RouterContext>

Guards and listeners

Navigation listeners

The route and router supports several navigation guards and listeners:

• beforeEnter to run before a route is resolved.
• beforeLeave to run before a route is removed.
• beforeEach to run before any route is resolved.

Guards trigger after url change and before the route component is rendered.

If a guard returns false, and object of instance Error or throws, the navigation will be aborted and the error will be thrown.

If a guard returns an object with a path or name property, the navigation will be redirected to the provided route, if any is found and followGuardRedirects is enabled.

The router (dynamically or through options) and RouterView also support several event listeners:

• onStart - executed when the navigation is triggered but before the route is resolved (fires on start and redirects).
• onEnd - executed when the navigation is triggered and the route is resolved (fires on successful and failed navigation, but not on cancelled/redirected).
• onError - executed when the navigation is triggered but an error occurs.

Note: The onError listeners passed to a RouterView will listen to both the router and view events. If you want to listen to only the router events, you can pass the listeners to the router options or instance directly.

Loading Listeners

The RouterView supports several view change listeners that triggers once the navigation concludes and the view starts changing.

• onChange - executed when a view starts to change.
• onLoading - executed when a view starts loading an async component.
• onLoaded - executed when a view finish loading a component.
• onError - executed when an error occurs during view change.

Note: The onError listeners passed to a RouterView will listen to both the router and view events. If you want to listen to only the view events, you can pass the listeners to the view instance directly.

Lazy routing

The Route object supports lazy loading of the route component(s).

When the component property is a lazy import, the router will resolve the matched component before rendering it.

While the component is being resolved, the loading component will be rendered if any, the loading snippet if any, or nothing.

Similarly, if an error occurs during the component resolution, the error component will be rendered if any, the error snippet if any, or nothing.

The router will try to infer if a component is a lazy import by checking it's name, but for more complex cases, you can use the toLazyComponent wrapper. Nested lazy components require the wrapper to be used or the function to be manually named component.

<script lang="ts">
    import { RouterView } from '@dvcol/svelte-simple-router/components';
    import { toLazyComponent } from '@dvcol/svelte-simple-router/utils';
    
    import type { Route, RouterOptions } from '@dvcol/svelte-simple-router/models';
    
    const routes: Readonly<Route[]> = [
        {
            name: 'lazy',
            path: '/lazy',
            component: () => import('./LazyComponent.svelte'),
            loading: () => import('./LoadingComponent.svelte'),
            error: () => import('./ErrorComponent.svelte'),
        },
        {
            name: 'lazy-snippet',
            path: '/lazy-snippet',
            component: () => import('./LazyComponent.svelte')
        },
        {
            name: 'lazy-nested',
            path: '/lazy-nested',
            components: {
                default: toLazyComponent(() => import('./LazyComponent.svelte')),
                nested: toLazyComponent(() => import('./NestedComponent.svelte')),
            }
        }
    ] as const;
</script>

<RouterView {routes}>
  {#snippet loading()}
    <h1>Default Loading...</h1>
  {/snippet}

  {#snippet error(err)}
    <h1>Default Error: {err}</h1>
  {/snippet}
</RouterView>

Note that loading indicator only trigger once the route has been resolved and not on initial navigation. If you want to show a loading indicator on initial navigation, you can use the routing snippet instead.

This means navigation will be a three-step process:

• The routing snippet will be rendered.
• Then the loading component will be rendered.
• Then the route component or error component will be rendered.

Routes

• Route path supports parameters. Parameters are defined by a colon followed by the parameter name.

/path/:param

• Parameters can be optional by adding a question mark.

/path/:param?

Parameters can also have a type constraint by adding :{string} or :{number} before the parameter name.

The router will only match the route if the parameter matches the type constraint.

/path/:{string}:param?

Will match /path/param but not /path/1.

/path/:{number}:param

Will match /path/1 but not /path/param.

• Route support wildcards. The * character will match any path segment.

/path/*

Will match /path/param and /path/param/param.

/path/*/:{number}:param/*

Will match /path/any/12 and /path/other/12/path/end.

• Route can have a redirect property to redirect to another route (by path or name).
• Route can have components, loadings or errors properties to render the route component, loading component or error component respectively (see lazy-routing).
• Route can have a meta property to store additional information attached to the route.
• Route can have a title property to set the document title when the route is active (if nameAsTitle is enabled).
• Route can have default query or params to be used when navigating to the route.
• Route can have guard properties to run before the route is resolved (see guards and listeners).
• Route can provide their own matcher object to resolve the active route.
• Route can have children routes that will be parsed by the router instance.

Router

In addition to default navigation options (see programmatic navigation), the router instance supports several options:

• history to set the history instance the router will use (defaults to global.history).
• location to set the location instance the router will use (defaults to global.location).
• listen to listen to popstate or navigation events and trigger synchronization.
• priority to set the priority when multiple routes match the current path.
• caseSensitive to enable case sensitive route names.
• And various guards and listeners.

Author

• Github: @dvcol

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📝 License

This project is MIT licensed.

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