As a general rule, data flow in Svelte is top down — a parent component can set props on a child component, and a component can set attributes on an element, but not the other way around.

Sometimes it's useful to break that rule. Take the case of the <input> element in this component — we could add an on:input event handler that sets the value of name to, but it's a bit... boilerplatey. It gets even worse with other form elements, as we'll see.

Instead, we can use the bind:value directive:

<input bind:value={name}>

This means that not only will changes to the value of name update the input value, but changes to the input value will update name.