createExtension

createExtension defines an extension: a named unit of API that adds its own namespace to the client. It bundles procedures (exposed under the extension's id) and webhook event handlers. Register the result on your server through createKizlo's extensions array.

Parameters

createExtension(extension)

id

The extension's namespace: a string literal, unique across registered extensions. It becomes the key on the client, so a procedure at router.get on an extension with id: "featured" is called as client.featured.get(...).

init

A function returning what the extension exposes. Both fields are optional, so an extension can expose a router, handle events, or both:

Returns

The extension object, typed. Pass it to createKizlo({ extensions: [...] }) to mount its namespace on the client and its routes on the handler.

Examples

Wrap the call in a factory function (a plain function that returns the extension) so each app creates its own instance and can pass options in later:

import { createEventHandler, createExtension, createProcedure } from "kizlo"
import { z } from "zod"

export const reviews = () =>
  createExtension({
    id: "reviews",
    init: () => ({
      router: {
        list: createProcedure(
          { scope: "api", method: "GET", path: "/reviews", output: z.array(z.object({ id: z.number() })) },
          async () => [{ id: 1 }],
        ),
      },
      events: [
        createEventHandler(async (event, context) => {
          if (event) context.logger.info("webhook received", { type: event.type })
        }),
      ],
    }),
  })

Register it, and client.reviews.list() is typed from the procedure's output:

import { reviews } from "./reviews"

export const { client, handler } = createKizlo({
  extensions: [reviews()],
})