H3 App Instance

You can create a new h3 app instance using new H3():

import { H3 } from "h3";

const app = new H3(/* optional config */);

H3 App Options

You can pass global app configuration when initializing an app.

Example: Create an app with verbose logging enabled.

const app = new H3({ debug: true });

Global Hooks

When initializing an h3 app, you can register global hooks:

• onError
• onRequest
• onBeforeResponse

These hooks are called for every request and can be used to add global logic to your app such as logging, error handling, etc.

const app = new H3({
  onError: (error) => {
    console.error(error);
  },
  onRequest: (event) => {
    console.log("Request:", event.path);
  },
});

H3 App Methods

app.fetch(request, init?, context?)

A fetch-like API allowing to fetch app routes.

Input can be a URL, relative path or standard Request object.

Returned value is a standard Response or a promise resolving to a Response.

Example:

const response = await app.fetch("/");

console.log(response, await response.text());

app.handler(event)

An h3 compatible event handler useful to compose multiple h3 app instances.

app.resolve(method, path)

Resolve a route handler by method and path useful for custom purposes.

app.on(method, route, handler)

Register route handler for specific HTTP method.

app.[method](route, handler)

Register route handler for specific HTTP method (shortcut for app.on(method, ...)).

app.all(route, handler)

Register route handler for all HTTP methods.

app.use(handler, opts?)

Register a global middleware handler.

app.use(route, handler, opts?)

Register a routed global middleware handler.

H3 App Properties

app.config

Global h3 instance config.

app.websocket

Websocket hooks compatible with 🔌 crossws.