useRef

Returns an empty mutable Ref object.

To initialize a ref with a value, use useRefInit instead.

Changes to the Ref.current property do not cause the containing function component to re-render.

The returned Ref object will persist for the full lifetime of the function component. Compare to createRef which returns a new Ref object on each render.

Note: there are two rules for using Hooks:

• Only call Hooks at the top level.
• Only call Hooks from inside a function component.

Example:

final MyComponent = registerFunctionComponent((props) {
  final inputRef = useRef<InputElement>(null);
return div(children: [
input({'ref': inputRef.jsRef}),
button(text: 'Focus', onClick: () => inputRef.current?.focus()),
]);
});

• useRef documentation
• useRef 是一个 React Hook，它能帮助引用一个不需要渲染的值