Basics · Bindings

Two-way bind:value

A text <input> owns its own edit buffer — the cursor, the text, the view offset. To connect that buffer to a signal, use bind:value. It is two-way: the control writes the signal as the user types, and an external write to the signal updates the rendered control.

bind:value expects a *sumi.Signal[string]; a type mismatch is a plain Go compile error. In the starting app the input isn’t bound, so the preview line below it never updates.

Under the hood bind:value is sugar for wiring the input’s input event to a handler that mirrors the value. If you need to transform or validate instead of just mirroring, drop to that event yourself with oninput={...} and read evt.Data["value"].(string). Use one or the other: declaring bind:value and oninput on the same input is a generation error.

Your turn

Bind the input to the draft signal:

<input type="text" bind:value={draft} />

Press Run, click into the input, and type — the preview line tracks every keystroke.