The <textarea> element behaves similarly to a text input in Svelte — use bind:value:

<textarea bind:value={value}></textarea>

In cases like these, where the names match, we can also use a shorthand form:

<textarea bind:value></textarea>

This applies to all bindings, not just textareas.

App.svelte

Console

Compiler options

result = svelte.compile(source, {
generate:
});