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SvelteKit makes a number of modules available to your application.


import { browser, dev, prerendering } from '$app/env';


true if the app is running in the browser.

const browser: boolean;


Whether the dev server is running. This is not guaranteed to correspond to NODE_ENV or MODE.

const dev: boolean;


true when prerendering, false otherwise.

const prerendering: boolean;


import {
} from '$app/navigation';


A lifecycle function that runs when the page mounts, and also whenever SvelteKit navigates to a new URL but stays on this component.

function afterNavigate(
  fn: (navigation: { from: URL | null; to: URL }) => void
): void;


A navigation interceptor that triggers before we navigate to a new URL (internal or external) whether by clicking a link, calling goto, or using the browser back/forward controls. This is helpful if we want to conditionally prevent a navigation from completing or lookup the upcoming url.

function beforeNavigate(
  fn: (navigation: { from: URL; to: URL | null; cancel: () => void }) => void
): void;


If called when the page is being updated following a navigation (in onMount or afterNavigate or an action, for example), this disables SvelteKit's built-in scroll handling. This is generally discouraged, since it breaks user expectations.

function disableScrollHandling(): void;


Returns a Promise that resolves when SvelteKit navigates (or fails to navigate, in which case the promise rejects) to the specified url.

function goto(
  url: string | URL,
  opts?: {
    replaceState?: boolean;
    noscroll?: boolean;
    keepfocus?: boolean;
    state?: any;
): Promise<void>;


Causes any load functions belonging to the currently active page to re-run if they fetch the resource in question, or re-fetches data from a page endpoint if the invalidated resource is the page itself. Returns a Promise that resolves when the page is subsequently updated.

function invalidate(
  dependency: string | ((href: string) => boolean)
): Promise<void>;


Programmatically prefetches the given page, which means

  1. ensuring that the code for the page is loaded, and
  2. calling the page's load function with the appropriate options.

This is the same behaviour that SvelteKit triggers when the user taps or mouses over an <a> element with sveltekit:prefetch. If the next navigation is to href, the values returned from load will be used, making navigation instantaneous. Returns a Promise that resolves when the prefetch is complete.

function prefetch(href: string): Promise<void>;


Programmatically prefetches the code for routes that haven't yet been fetched. Typically, you might call this to speed up subsequent navigation.

If no argument is given, all routes will be fetched, otherwise you can specify routes by any matching pathname such as /about (to match src/routes/about.svelte) or /blog/* (to match src/routes/blog/[slug].svelte).

Unlike prefetch, this won't call load for individual pages. Returns a Promise that resolves when the routes have been prefetched.

function prefetchRoutes(routes?: string[]): Promise<void>;


import { base, assets } from '$app/paths';


An absolute path that matches config.kit.paths.assets.

If a value for config.kit.paths.assets is specified, it will be replaced with '/_svelte_kit_assets' during vite dev or vite preview, since the assets don't yet live at their eventual URL.

const assets: `https://${string}` | `http://${string}`;


A string that matches config.kit.paths.base. It must start, but not end with / (e.g. /base-path), unless it is the empty string.

const base: `/${string}`;


import { getStores, navigating, page, session, updated } from '$app/stores';

Stores are contextual — they are added to the context of your root component. This means that session and page are unique to each request on the server, rather than shared between multiple requests handled by the same server simultaneously, which is what makes it safe to include user-specific data in session.

Because of that, you must subscribe to the stores during component initialization (which happens automatically if you reference the store value, e.g. as $page, in a component) before you can use them.


A convenience function around getContext. Must be called during component initialization. Only use this if you need to defer store subscription until after the component has mounted, for some reason.

function getStores(): {
  navigating: typeof navigating;
  page: typeof page;
  session: typeof session;
  updated: typeof updated;


A readable store. When navigating starts, its value is { from: URL, to: URL }, When navigating finishes, its value reverts to null.

const navigating: Readable<Navigation | null>;


A readable store whose value contains page data.

const page: Readable<Page>;


A writable store whose initial value is whatever was returned from getSession. It can be written to, but this will not cause changes to persist on the server — this is something you must implement yourself.

const session: Writable<App.Session>;


A readable store whose initial value is false. If version.pollInterval is a non-zero value, SvelteKit will poll for new versions of the app and update the store value to true when it detects one. updated.check() will force an immediate check, regardless of polling.

const updated: Readable<boolean> & { check: () => boolean };


This module provides access to runtime environment variables, as defined by the platform you're running on. For example if you're using adapter-node (or running vite preview), this is equivalent to process.env. This module only includes variables that do not begin with config.kit.env.publicPrefix.

This module cannot be imported into client-side code.

import { env } from '$env/dynamic/private';


let env: App.PrivateEnv;


Similar to $env/dynamic/private, but only includes variables that begin with config.kit.env.publicPrefix (which defaults to PUBLIC_), and can therefore safely be exposed to client-side code

Note that public dynamic environment variables must all be sent from the server to the client, causing larger network requests — when possible, use $env/static/public instead.

import { env } from '$env/dynamic/public';


let env: App.PublicEnv;


Environment variables loaded by Vite from .env files and process.env. Like $env/dynamic/private, this module cannot be imported into client-side code. This module only includes variables that do not begin with config.kit.env.publicPrefix.

Unlike $env/dynamic/private, the values exported from this module are statically injected into your bundle at build time, enabling optimisations like dead code elimination.

import { API_KEY } from '$env/static/private';


Similar to $env/static/private, except that it only includes environment variables that begin with config.kit.env.publicPrefix (which defaults to PUBLIC_), and can therefore safely be exposed to client-side code.

Values are replaced statically at build time.

import { PUBLIC_BASE_URL } from '$env/static/public';


This is a simple alias to src/lib, or whatever directory is specified as config.kit.files.lib. It allows you to access common components and utility modules without ../../../../ nonsense.


import { build, files, prerendered, version } from '$service-worker';

This module is only available to service workers.


An array of URL strings representing the files generated by Vite, suitable for caching with cache.addAll(build).

const build: string[];


An array of URL strings representing the files in your static directory, or whatever directory is specified by config.kit.files.assets. You can customize which files are included from static directory using config.kit.serviceWorker.files

const files: string[];


An array of pathnames corresponding to prerendered pages and endpoints.

const prerendered: string[];


See config.kit.version. It's useful for generating unique cache names inside your service worker, so that a later deployment of your app can invalidate old caches.

const version: string;



A helper function for sequencing multiple handle calls in a middleware-like manner.

import { sequence } from '@sveltejs/kit/hooks';
/** @type {import('@sveltejs/kit').Handle} */
async function first({ event, resolve }) {
console.log('first pre-processing');
const result = await resolve(event);
console.log('first post-processing');
return result;
/** @type {import('@sveltejs/kit').Handle} */
async function second({ event, resolve }) {
console.log('second pre-processing');
const result = await resolve(event);
console.log('second post-processing');
return result;
export const handle = sequence(first, second);

The example above would print:

first pre-processing
second pre-processing
second post-processing
first post-processing
function sequence(...handlers: Handle[]): Handle;


Utilities used by adapters for Node-like environments.


function getRequest(
  base: string,
  request: import('http').IncomingMessage
): Promise<Request>;


function setResponse(
  res: import('http').ServerResponse,
  response: Response
): void;


A polyfill for fetch and its related interfaces, used by adapters for environments that don't provide a native implementation.


Make various web APIs available as globals:

  • crypto
  • fetch
  • Headers
  • Request
  • Response
function installPolyfills(): void;



Returns the SvelteKit Vite plugins.

function sveltekit(): Plugin[];
previous Hooks
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