Getting Started Qwikly

Qwik is a new kind of framework that is resumable (no eager JS execution and no hydration), built for the edge and familiar to React developers.

To play with it right away, check out our in-browser playgrounds:

• StackBlitz Qwik (Full Qwik + Qwikcity integration)
• Examples playground (Qwik only, no routing)

Prerequisites

To get started with Qwik locally, you need the following:

• Node.js v16.8 or higher
• Your favorite IDE (vscode recommended)
• Optionally, read think qwik

Create an app using the CLI

First, create a Qwik application with the Qwik CLI, which generates a blank starter so that you can quickly familiarize yourself with it.

Run the Qwik CLI in your shell. Qwik supports NPM, yarn and pnpm. Choose the package manager you prefer and run one of the following commands:

npm create qwik@latest
pnpm create qwik@latest
yarn create qwik
bun create qwik@latest

The CLI guides you through an interactive menu to set the project-name, select one of the starters and asks if you want to install the dependencies. Find out more about the files generated by referring to the Project Structure documentation.

Start the development server:

npm start
pnpm start
yarn start
bun start

Qwik Joke App

The Qwik Hello World tutorial guides you through building a joke app with Qwik while covering the most important Qwik concepts. The app displays a random joke from https://icanhazdadjoke.com and features a button to get a new joke on click.

1. Create A Route

Start by serving a page at a particular route. This basic app serves a random dad joke application on the /joke/ route. This tutorial relies on Qwikcity, Qwik's meta-framework, which uses directory-based routing. To get started:

1. In your project, create a new joke directory in routes containing an index.tsx file.
2. Each route's index.tsx file must have an export default component$(...) so that Qwikcity knows what content to serve. Paste the following content to src/routes/joke/index.tsx:

import { component$ } from '@builder.io/qwik';
 
export default component$(() => {
  return <section class="section bright">A Joke!</section>;
});

3. Navigate to http://127.0.0.1:5173/joke/ to see your new page working.

NOTE:

• Your joke route default component is surrounded by an existing layout. See Layout for more details on what layouts are and how to work with them.
• For more details about how to author components, see the Component API section.

2. Loading Data

We will use the external JSON API at https://icanhazdadjoke.com to load random jokes. We will use route loaders, to load this data in the server and then render it in the component.

1. Open src/routes/joke/index.tsx and add this code:

import { component$ } from '@builder.io/qwik';
import { routeLoader$ } from '@builder.io/qwik-city';
 
export const useDadJoke = routeLoader$(async () => {
  const response = await fetch('https://icanhazdadjoke.com/', {
    headers: { Accept: 'application/json' },
  });
  return (await response.json()) as {
    id: string;
    status: number;
    joke: string;
  };
});
 
export default component$(() => {
  // Calling our `useDadJoke` hook, will return a reactive signal to the loaded data.
  const dadJokeSignal = useDadJoke();
  return (
    <section class="section bright">
      <p>{dadJokeSignal.value.joke}</p>
    </section>
  );
});

2. Now on http://localhost:5173/joke/, the browser displays a random joke.

Code explanation:

• The function passed to routeLoader$ is invoked on the server eagerly before any component is rendered and is responsible for loading data.
• The routeLoader$ returns a use-hook, useDadJoke(), that can be used in the component to retrieve the server data.

NOTE

• The routeLoader$ is invoked eagerly on the server before any component is rendered, even if its use-hook is not invoked in any component.
• The routeLoader$ return type is inferred in the component without the need for any additional type information.

3. Posting Data to the Server

Previously, we used routeLoader$ to send data from the server to the client. To post (send) data from the client back to the server, we use routeAction$ .

NOTE: routeAction$ is the preferred way to send data to the server because it uses the browser native form API, which works even if JavaScript is disabled.

To declare an action, add this code:

import { routeLoader$, Form, routeAction$ } from '@builder.io/qwik-city';
 
export const useJokeVoteAction = routeAction$((props) => {
  // Leave it as an exercise for the reader to implement this.
  console.log('VOTE', props);
});

2. Update the export default component to use the useJokeVoteAction hook with <Form>.

export default component$(() => {
  const dadJokeSignal = useDadJoke();
  const favoriteJokeAction = useJokeVoteAction();
  return (
    <section class="section bright">
      <p>{dadJokeSignal.value.joke}</p>
      <Form action={favoriteJokeAction}>
        <input type="hidden" name="jokeID" value={dadJokeSignal.value.id} />
        <button name="vote" value="up">👍</button>
        <button name="vote" value="down">👎</button>
      </Form>
    </section>
  );
});

3. Now on http://localhost:5173/joke/, the buttons display and if you click them, their value logs to the console.

Code explanation:

• routeAction$ receives the data.
  • The function passed to routeAction$ is invoked on the server whenever the form is posted.
  • The routeAction$ returns a use-hook, useJokeVoteAction, that you can use in the component to post the form data.
• Form is a convenience component that wraps the browser's native <form> element.

Things to note:

• For validation, see zod validation.
• The routeAction$ works even if JavaScript is disabled.
• If JavaScript is enabled, the Form component will prevent the browser from posting the form and instead post the data using JavaScript and emulate the browser's native form behavior without a full refresh.

For reference, the complete code snippet for this section is as follows:

import { component$ } from '@builder.io/qwik';
import { routeLoader$, Form, routeAction$ } from '@builder.io/qwik-city';
 
export const useDadJoke = routeLoader$(async () => {
  const response = await fetch('https://icanhazdadjoke.com/', {
    headers: { Accept: 'application/json' },
  });
  return (await response.json()) as {
    id: string;
    status: number;
    joke: string;
  };
});
 
export const useJokeVoteAction = routeAction$((props) => {
  console.log('VOTE', props);
});
 
export default component$(() => {
  // Calling our `useDadJoke` hook, will return a reactive signal to the loaded data.
  const dadJokeSignal = useDadJoke();
  const favoriteJokeAction = useJokeVoteAction();
  return (
    <section class="section bright">
      <p>{dadJokeSignal.value.joke}</p>
      <Form action={favoriteJokeAction}>
        <input type="hidden" name="jokeID" value={dadJokeSignal.value.id} />
        <button name="vote" value="up">
          👍
        </button>
        <button name="vote" value="down">
          👎
        </button>
      </Form>
    </section>
  );
});

4. Modifying State

Keeping track of the state and updating the UI is core to what applications do. Qwik provides a useSignal hook to keep track of the application's state. To learn more, see state management.

To declare state:

1. Import useSignal from qwik.

   import { component$, useSignal } from "@builder.io/qwik";

2. Declare the component's state using useSignal().

   const isFavoriteSignal = useSignal(false);

3. After the closing Form tag, add a button to the component to modify the state.

   <button
    onClick$={() => {
      isFavoriteSignal.value = !isFavoriteSignal.value;
    }}>
     {isFavoriteSignal.value ? '❤️' : '🤍'}
   </button>

NOTE: Clicking on the button updates the state, which in turn updates the UI.

For reference, the complete code snippet for this section is as follows:

import { component$, useSignal } from '@builder.io/qwik';
import { routeLoader$, Form, routeAction$ } from '@builder.io/qwik-city';
 
export const useDadJoke = routeLoader$(async () => {
  const response = await fetch('https://icanhazdadjoke.com/', {
    headers: { Accept: 'application/json' },
  });
  return (await response.json()) as {
    id: string;
    status: number;
    joke: string;
  };
});
 
export const useJokeVoteAction = routeAction$((props) => {
  console.log('VOTE', props);
});
 
export default component$(() => {
  const isFavoriteSignal = useSignal(false);
  // Calling our `useDadJoke` hook, will return a reactive signal to the loaded data.
  const dadJokeSignal = useDadJoke();
  const favoriteJokeAction = useJokeVoteAction();
 
  return (
    <section class="section bright">
      <p>{dadJokeSignal.value.joke}</p>
      <Form action={favoriteJokeAction}>
        <input type="hidden" name="jokeID" value={dadJokeSignal.value.id} />
        <button name="vote" value="up">
          👍
        </button>
        <button name="vote" value="down">
          👎
        </button>
      </Form>
      <button
        onClick$={() => (isFavoriteSignal.value = !isFavoriteSignal.value)}
      >
        {isFavoriteSignal.value ? '❤️' : '🤍'}
      </button>
    </section>
  );
});

5. Tasks and Invoking Server Code

In Qwik, a task is work that needs to happen when a state changes. (This is similar to an "effect" in other frameworks.) In this example, we use the task to invoke code on the server.

1. Import useTask$ from qwik.

   import { component$, useSignal, useTask$ } from "@builder.io/qwik";

2. Create a new task that tracks the isFavoriteSignal state:

   useTask$(({ track }) => {});

3. Add a track call to re-execute the task on isFavoriteSignal state change:

   useTask$(({ track }) => {
     track(() => isFavoriteSignal.value);
   });

4. Add the work that you want to execute on state change:

   useTask$(({ track }) => {
     track(() => isFavoriteSignal.value);
     console.log('FAVORITE (isomorphic)', isFavoriteSignal.value);
   });

5. If you want to have work happen on the server only, wrap it in server$()

   useTask$(({ track }) => {
     track(() => isFavoriteSignal.value);
     console.log('FAVORITE (isomorphic)', isFavoriteSignal.value);
     server$(() => {
       console.log('FAVORITE (server)', isFavoriteSignal.value);
     })();
   });

NOTE:

• The body of useTask$ is executed on both the server and the client (isomorphic).
• On SSR, the server prints FAVORITE (isomorphic) false and FAVORITE (server) false.
• When the user interacts with favorite, the client prints FAVORITE (isomorphic) true and the server prints FAVORITE (server) true.

For reference, the complete code snippet for this section is as follows:

import { component$, useSignal, useTask$ } from '@builder.io/qwik';
import {
  routeLoader$,
  Form,
  routeAction$,
  server$,
} from '@builder.io/qwik-city';
 
export const useDadJoke = routeLoader$(async () => {
  const response = await fetch('https://icanhazdadjoke.com/', {
    headers: { Accept: 'application/json' },
  });
  return (await response.json()) as {
    id: string;
    status: number;
    joke: string;
  };
});
 
export const useJokeVoteAction = routeAction$((props) => {
  console.log('VOTE', props);
});
 
export default component$(() => {
  const isFavoriteSignal = useSignal(false);
  // Calling our `useDadJoke` hook, will return a reactive signal to the loaded data.
  const dadJokeSignal = useDadJoke();
  const favoriteJokeAction = useJokeVoteAction();
  useTask$(({ track }) => {
    track(() => isFavoriteSignal.value);
    console.log('FAVORITE (isomorphic)', isFavoriteSignal.value);
    server$(() => {
      console.log('FAVORITE (server)', isFavoriteSignal.value);
    })();
  });
  return (
    <section class="section bright">
      <p>{dadJokeSignal.value.joke}</p>
      <Form action={favoriteJokeAction}>
        <input type="hidden" name="jokeID" value={dadJokeSignal.value.id} />
        <button name="vote" value="up">
          👍
        </button>
        <button name="vote" value="down">
          👎
        </button>
      </Form>
      <button
        onClick$={() => (isFavoriteSignal.value = !isFavoriteSignal.value)}
      >
        {isFavoriteSignal.value ? '❤️' : '🤍'}
      </button>
    </section>
  );
});

6. Styling

Styling is an important part of any application. Qwik provides a way to associate and scope styles with your component.

To add styles:

1. Create a new file src/routes/joke/index.css:

   p {
     font-weight: bold;
   }
    
   form {
     float: right;
   }

2. import the styles in src/routes/joke/index.tsx:

   import styles from "./index.css?inline";

3. Import useStylesScoped$ from qwik.

   import { component$, useSignal, useStylesScoped$, useTask$ } from "@builder.io/qwik";

4. Tell the component to load the styles:

   useStylesScoped$(styles);

Code explanation:

• The ?inline query parameter tells Vite to inline the styles into the component.
• The useStylesScoped$ call tells Qwik to associate the styles with the component only (scoping).
• Styles are only loaded if they are not already inlined as part of SSR and only for the first component.

For reference, the complete code snippet for this section is as follows:

import {
  component$,
  useSignal,
  useStylesScoped$,
  useTask$,
} from '@builder.io/qwik';
import {
  routeLoader$,
  Form,
  routeAction$,
  server$,
} from '@builder.io/qwik-city';
import styles from './index.css?inline';
 
export const useDadJoke = routeLoader$(async () => {
  const response = await fetch('https://icanhazdadjoke.com/', {
    headers: { Accept: 'application/json' },
  });
  return (await response.json()) as {
    id: string;
    status: number;
    joke: string;
  };
});
 
export const useJokeVoteAction = routeAction$((props) => {
  console.log('VOTE', props);
});
 
export default component$(() => {
  useStylesScoped$(styles);
  const isFavoriteSignal = useSignal(false);
  // Calling our `useDadJoke` hook, will return a reactive signal to the loaded data.
  const dadJokeSignal = useDadJoke();
  const favoriteJokeAction = useJokeVoteAction();
  useTask$(({ track }) => {
    track(() => isFavoriteSignal.value);
    console.log('FAVORITE (isomorphic)', isFavoriteSignal.value);
    server$(() => {
      console.log('FAVORITE (server)', isFavoriteSignal.value);
    })();
  });
  return (
    <section class="section bright">
      <p>{dadJokeSignal.value.joke}</p>
      <Form action={favoriteJokeAction}>
        <input type="hidden" name="jokeID" value={dadJokeSignal.value.id} />
        <button name="vote" value="up">👍</button>
        <button name="vote" value="down">👎</button>
      </Form>
      <button
        onClick$={() => (isFavoriteSignal.value = !isFavoriteSignal.value)}
      >
        {isFavoriteSignal.value ? '❤️' : '🤍'}
      </button>
    </section>
  );
});

7. Preview

We built a minimal application that gave you an overview of key Qwik concepts and API. The application is running in dev mode, which uses hot-module-reloading (HMR) to continuously update the application while changing the code.

While in dev mode:

• Each file is loaded individually, which may cause waterfalls in the network tab.
• There is no speculative loading of bundles, so there may be a delay on the first interaction.

Let's create a production build that eliminates these issues.

To create a preview build:

1. Run npm run preview to create a production build.

NOTE:

• Your application should have a production build now and be running on a different port.
• If you interact with the application now, the network tab of the dev tools should show that the bundles are instantly delivered from the ServiceWorker cache.

Review

Congratulations! You've learned a lot about Qwik! For more on just how much you can achieve with Qwik, we recommend reading the dedicated docs on each of the topics touched on in this tutorial:

• Project structure
• Directory-based routing
• Component
• Route loaders
• Form actions && zod validation
• State management
• Tasks
• ServiceWorker cache