asijs-sveltekit — SvelteKit Adapter

Use AsiJS routing inside SvelteKit. Two integration points: a handle hook that intercepts API requests (everything else falls through to SvelteKit), and per-method +server.ts handlers.

• Package: asijs-sveltekit
• Requires: asijs (peer dependency)
• Supports: SvelteKit 2+

Installation

bun add asijs-sveltekit

1. Server hook (handle)

// src/hooks.server.ts
import { Asi } from "asijs";
import { createSvelteKitHook } from "asijs-sveltekit";

const app = new Asi();
app.get("/api/hello", () => "Hello from AsiJS + SvelteKit!");

export const handle = createSvelteKitHook(app, { basePath: "/api" });

The hook intercepts requests whose path starts with the basePath and routes them through AsiJS. Everything else is passed through to SvelteKit's resolve() — pages, endpoints, static assets keep working normally.

2. Per-method server route

// src/routes/api/[...asi]/+server.ts
import { Asi } from "asijs";
import { createServerHandler } from "asijs-sveltekit";

const app = new Asi();
app.get("/api/hello", () => ({ message: "Hello!" }));
app.post("/api/data", async (ctx) => {
  const body = await ctx.json();
  return { received: body };
});

export const GET = createServerHandler(app, "GET");
export const POST = createServerHandler(app, "POST");

createServerHandler(app, method) returns a handler for exactly one verb and responds 405 Method Not Allowed when the incoming method doesn't match.

3. Universal handler

// src/routes/api/[...asi]/+server.ts
import { Asi } from "asijs";
import { createUniversalHandler } from "asijs-sveltekit";

const app = new Asi();

export const GET = createUniversalHandler(app);
export const POST = createUniversalHandler(app);
export const PUT = createUniversalHandler(app);

createUniversalHandler handles all HTTP methods with a single function — use it when the file shouldn't enforce per-method 405s (the AsiJS router itself returns 405/404 semantics).

Options

interface SvelteKitAdapterOptions {
  /** Base path prefix for API routes */
  basePath?: string;
  /** Enable verbose logging */
  verbose?: boolean;
  /** Custom error handler */
  onError?: (error: Error) => Response;
}

SvelteKit context integration

SvelteKit feature	AsiJS equivalent
event.locals	ctx.locals — shared data object, same reference
event.cookies	ctx.cookie(...) / ctx.cookies
event.platform	ctx.platform
event.clientAddress	passed through for trustProxy / logging
event.url	ctx.url (original URL preserved)

Because the adapter passes event.locals by reference, data written by AsiJS middleware is visible to later SvelteKit code (and vice versa) within the same request.

Streaming & SSE

SvelteKit handle hooks may return a Response — AsiJS's ctx.stream(), ctx.sse(), and ctx.eventStream() work unchanged:

app.get("/api/events", (ctx) =>
  ctx.sse((send) => {
    const t = setInterval(() => send({ data: JSON.stringify({ at: Date.now() }) }), 1000);
    return () => clearInterval(t);
  }),
);

Performance notes

1. Module-scope Asi instance — the route table builds once, not per request.
2. basePath matching is a string prefix check — keep it exact (/api not /api/) to avoid double-slash paths.
3. For heavy APIs, register the catch-all +server.ts with createUniversalHandler and let AsiJS do the routing — one file, all verbs, no per-file boilerplate.