useMount

React lifecycle hook that executes a function after the component is mounted

useMount runs a callback exactly once after the component mounts, equivalent to useEffect(() => { ... }, []). It provides a semantically clear way to express mount-only logic without manually specifying an empty dependency array. The callback receives no arguments and does not support a return-based cleanup function.

When to Use

• Running one-time initialization logic such as analytics tracking, logging, or third-party SDK setup
• Performing DOM measurements or imperative focus calls immediately after the component first renders
• Replacing class component componentDidMount behavior with a concise hook

Notes

• No cleanup: useMount does not support a cleanup return value. If you need unmount cleanup, pair it with useUnmount or use useEffect directly.
• Development validation: In development mode, a console error is logged if the provided argument is not a function.
• See also useUnmount for the corresponding unmount lifecycle, and useOnceEffect if you need React 18 Strict Mode double-invoke protection.

Usage

function Demo() {
  const [value, setValue] = useState("UnMounted");
  useMount(() => {
    setValue("Mounted");
  });
  return <div>{value}</div>;
};

API

useMount

Returns

void

Arguments