SvelteKit provides several hooks — ways to intercept and override the framework's default behaviour.
The most elementary hook is handle, which lives in src/hooks.server.js. It receives an event object along with a resolve function, and returns a Response.
resolve is where the magic happens: SvelteKit matches the incoming request URL to a route of your app, imports the relevant code (+page.server.js and +page.svelte files and so on), loads the data needed by the route, and generates the response.
The default handle hook looks like this:
src/hooks.server.js
export async function handle({ event, resolve }) {
return await resolve(event);
}For pages (as opposed to API routes), you can modify the generated HTML with transformPageChunk:
src/hooks.server.js
export async function handle({ event, resolve }) {
return await resolve(event, {
transformPageChunk: ({ html }) => html.replace(
'<body',
'<body style="color: hotpink"'
)
});
}You can also create entirely new routes:
src/hooks.server.js
export async function handle({ event, resolve }) {
if (event.url.pathname === '/ping') {
return new Response('pong');
}
return await resolve(event, {
transformPageChunk: ({ html }) => html.replace(
'<body',
'<body style="color: hotpink"'
)
});
}