H3

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

import { H3 } from "h3";

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

#H3 Methods

#H3.request

A fetch-compatible function allowing to fetch app routes.

• Input can be a relative path, URL, or Request.
• Returned value is a Response promise.

const response = await app.request("/");
console.log(response, await response.text());

#H3.fetch

Similar to H3.request but only accepts one (req: Request) argument for cross runtime compatibility.

#H3.on

Register route handler for specific HTTP method.

const app = new H3().on("GET", "/", () => "OK");

#H3.[method]

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

const app = new H3().get("/", () => "OK");

#H3.all

Register route handler for all HTTP methods.

const app = new H3().all("/", () => "OK");

#H3.use

Register a global middleware.

const app = new H3()
  .use((event) => {
    console.log(`request: ${event.req.url}`);
  })
  .all("/", () => "OK");

#H3.register

Register a H3 plugin to extend app.

#H3.handler

An H3 event handler useful to compose multiple H3 app instances.

Example: Nested apps.

import { H3, serve, redirect, withBase } from "h3";

const nestedApp = new H3().get("/test", () => "/test (sub app)");

const app = new H3()
  .get("/", (event) => redirect(event, "/api/test"))
  .all("/api/**", withBase("/api", nestedApp.handler));

serve(app);

#H3.mount

Using .mount method, you can register a sub-app with prefix.

#H3 Options

You can pass global app configuration when initializing an app.

Supported options:

• debug: Displays debugging stack traces in HTTP responses (potentially dangerous for production!).
• silent: When enabled, console errors for unhandled exceptions will not be displayed.
• allowMalformedURL: When enabled, requests with a malformed percent-encoded URL path (e.g. /foo%, /%ZZ) are allowed through with the raw pathname instead of being rejected with a 400 Bad Request (the default).
• plugins: (see plugins for more information)

#Global Hooks

When initializing an H3 app, you can register global hooks:

• onError
• onRequest
• onResponse

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({
  onRequest: (event) => {
    console.log("Request:", event.req.url);
  },
  onResponse: (response, event) => {
    console.log("Response:", event.url.pathname, response.status);
  },
  onError: (error, event) => {
    console.error(error);
  },
});

#H3 Properties

#H3.config

Global H3 instance config.