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Sveltejs Academy · Lesson

bind:group for Radio and Checkbox Groups

Synchronize a group of related inputs to a single variable.

bind:group for Radio and Checkbox Groups is a free Sveltejs Academy lesson on CoddyKit — lesson 3 of 4. You can read the complete lesson below for free — then practise it hands-on in the browser with a built-in code editor and a 24/7 AI tutor. It is part of the Sveltejs Academy learning path, one of 4 lessons in the course, and your progress syncs across the web and the CoddyKit app.

Radio Groups

For mutually exclusive options, use multiple radios with the same bind:group variable.

<input type="radio" bind:group={size} value="sm" /> S
<input type="radio" bind:group={size} value="md" /> M
<input type="radio" bind:group={size} value="lg" /> L

How It Works

The bound variable equals the value of the selected radio.

Initial Value

Initialize the variable to the value of the default-selected option.

let size = "md";

Checkbox Groups

For multi-select, bind a group of checkboxes to an array.

<input type="checkbox" bind:group={tags} value="bug" /> Bug
<input type="checkbox" bind:group={tags} value="docs" /> Docs

Array Behavior

The bound array holds the values of all currently checked boxes. Adds and removes happen automatically.

Initialize Array

Start with an empty array or with pre-selected values.

let tags = ["bug"];

Mixing with Other Inputs

You can bind value and group in the same form for hybrid UIs.

Iterating Options

Use {#each} to render options from data.

{#each sizes as size}
  <label><input type="radio" bind:group={chosen} value={size} /> {size}</label>
{/each}

Disabled Options

You can disable individual options without breaking the group binding.

Form Submission

When the form submits, the values reflect the bound variable.

Validation

Combine with reactive checks to require at least one selection.

$: hasSelection = tags.length > 0;

Quick Check

For checkbox groups, what type is the bound variable?

Recap

Use bind:group with shared variable for radios (string) and checkboxes (array of values).

Frequently asked questions

Is the “bind:group for Radio and Checkbox Groups” lesson free?

Yes — the full text of “bind:group for Radio and Checkbox Groups” is free to read here on the web, and the Sveltejs Academy course includes 4 lessons in total. To practise it interactively (a built-in code editor and a 24/7 AI tutor) and unlock the rest of the Sveltejs Academy course, upgrade to CoddyKit PRO.

What will I learn in “bind:group for Radio and Checkbox Groups”?

Synchronize a group of related inputs to a single variable. You practise Sveltejs Academy with hands-on code you run directly in the browser, and a 24/7 AI tutor answers your questions as you work through the lesson.

Do I need any experience to start Sveltejs Academy?

No prior experience is required. Sveltejs Academy on CoddyKit is structured for beginners through advanced learners; this is — lesson 3 of 4, so you can start here or from the beginning and move at your own pace.

How long does the “bind:group for Radio and Checkbox Groups” lesson take?

Most CoddyKit lessons take about 5–10 minutes. Each one is bite-sized and interactive, so you make steady progress and pick up exactly where you left off across the web and the app.

Can I write and run code in this Sveltejs Academy lesson?

Yes. Every Sveltejs Academy lesson includes a built-in code editor, so you write and run real code right in your browser and get instant AI feedback — no local setup required.

All lessons in this course

  1. bind:value for Text Inputs
  2. bind:checked for Checkboxes
  3. bind:group for Radio and Checkbox Groups
  4. bind:this for DOM Element References
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