forwardRef

const SomeComponent = forwardRef(render)

• Usage
  • Exposing a DOM node to the parent component
  • Forwarding a ref through multiple components
  • Exposing an imperative handle instead of a DOM node
• Reference
  • forwardRef(render)
  • render function
• Troubleshooting
  • My component is wrapped in forwardRef, but the ref to it is always null

Usage

Exposing a DOM node to the parent component

By default, each component’s DOM nodes are private. However, sometimes it’s useful to expose a DOM node to the parent—for example, to allow focusing it. To opt in, wrap your component definition into forwardRef():

import { forwardRef } from 'react';

const MyInput = forwardRef(function MyInput(props, ref) {
  const { label, ...otherProps } = props;
  return (
    <label>
      {label}
      <input {...otherProps} />
    </label>
  );
});

You will receive a ref as the second argument after props. Pass it to the DOM node that you want to expose:

import { forwardRef } from 'react';

const MyInput = forwardRef(function MyInput(props, ref) {
  const { label, ...otherProps } = props;
  return (
    <label>
      {label}
      <input {...otherProps} ref={ref} />
    </label>
  );
});

This lets the parent Form component access the <input> DOM node exposed by MyInput:

function Form() {
  const ref = useRef(null);

  function handleClick() {
    ref.current.focus();
  }

  return (
    <form>
      <MyInput label="Enter your name:" ref={ref} />
      <button type="button" onClick={handleClick}>
        Edit
      </button>
    </form>
  );
}

This Form component passes a ref to MyInput. The MyInput component forwards that ref to the <input> browser tag. As a result, the Form component can access that <input> DOM node and call focus() on it.

Keep in mind that by exposing a ref to the DOM node inside your component, you’re making it harder to change your component’s internals later. You will typically expose DOM nodes from reusable low-level components like buttons or text inputs, but you won’t do it for application-level components like an avatar or a comment.

Forwarding a ref through multiple components

Instead of forwarding a ref to a DOM node, you can forward it to your own component like MyInput:

const FormField = forwardRef(function FormField(props, ref) {
  // ...
  return (
    <>
      <MyInput ref={ref} />
      ...
    </>
  );
});

If that MyInput component forwards a ref to its <input>, a ref to FormField will give you that <input>:

function Form() {
  const ref = useRef(null);

  function handleClick() {
    ref.current.focus();
  }

  return (
    <form>
      <FormField label="Enter your name:" ref={ref} isRequired={true} />
      <button type="button" onClick={handleClick}>
        Edit
      </button>
    </form>
  );
}

The Form component defines a ref and passes it to FormField. The FormField component forwards that ref to MyInput, which forwards this ref to a browser <input> DOM node. This is how Form accesses that DOM node.

Exposing an imperative handle instead of a DOM node

Instead of exposing an entire DOM node, you can expose a custom object, called an imperative handle, with a more constrained set of methods. To do this, you’d need to define a separate ref to hold the DOM node:

const MyInput = forwardRef(function MyInput(props, ref) {
  const inputRef = useRef(null);

  // ...

  return <input {...props} ref={inputRef} />;
});

Then pass the ref you received to useImperativeHandle and specify the value you want to expose to the ref:

import { forwardRef, useRef, useImperativeHandle } from 'react';

const MyInput = forwardRef(function MyInput(props, ref) {
  const inputRef = useRef(null);

  useImperativeHandle(ref, () => {
    return {
      focus() {
        inputRef.current.focus();
      },
      scrollIntoView() {
        inputRef.current.scrollIntoView();
      },
    };
  }, []);

  return <input {...props} ref={inputRef} />;
});

If some component gets a ref to MyInput now, it will only receive your { focus, scrollIntoView } object instead of the DOM node. This lets you limit the information you expose about your DOM node to the minimum.

The methods you expose via an imperative handle don’t have to match the DOM methods exactly. For example, the Post component in the example below exposes a scrollAndFocusAddComment method via an imperative handle. This lets the parent Page scroll the list of comments and focus the input field when you click the button:

Read more about using imperative handles.

Reference

forwardRef(render)

Call forwardRef() to let your component receive a ref and forward it to a child component:

import { forwardRef } from 'react';

const MyInput = forwardRef(function MyInput(props, ref) {
  // ...
});

Parameters

• render: The render function for your component. React calls this function with the props and ref that your component received from its parent. The JSX you return will be the output of your component.

Returns

forwardRef returns a React component that you can render in JSX. Unlike React components defined as plain functions, a component returned by forwardRef is also able to receive a ref prop.

Caveats

• In Strict Mode, React will call your render function twice in order to help you find accidental impurities. This is development-only behavior and does not affect production. If your render function is pure (as it should be), this should not affect the logic of your component. The result from one of the calls will be ignored.

render function

forwardRef accepts a render function as an argument. React calls this function with props and ref:

const MyInput = forwardRef(function MyInput(props, ref) {
  return (
    <label>
      {props.label}
      <input ref={ref} />
    </label>
  );
});

Parameters

• props: The props passed by the parent component.

• ref: The ref attribute passed by the parent component. The ref can be an object or a function. If the parent component has not passed a ref, it will be null. You should either pass the ref you receive to another component, or pass it to useImperativeHandle.

Returns

forwardRef returns a React component that you can render in JSX. Unlike React components defined as plain functions, the component returned by forwardRef is able to take a ref prop.

Troubleshooting

My component is wrapped in forwardRef, but the ref to it is always null

This usually means that you forgot to actually use the ref that you received.

For example, this component doesn’t do anything with its ref:

const MyInput = forwardRef(function MyInput({ label }, ref) {
  return (
    <label>
      {label}
      <input />
    </label>
  );
});

To fix it, pass the ref down to a DOM node or another component that can accept a ref:

const MyInput = forwardRef(function MyInput({ label }, ref) {
  return (
    <label>
      {label}
      <input ref={ref} />
    </label>
  );
});

The ref to MyInput could also be null if some of the logic is conditional:

const MyInput = forwardRef(function MyInput({ label, showInput }, ref) {
  return (
    <label>
      {label}
      {showInput && <input ref={ref} />}
    </label>
  );
});

If showInput is false, then the ref won’t be forwarded to any node, and a ref to MyInput will remain empty. This is particularly easy to miss if the condition is hidden inside another component, like Panel in this example:

const MyInput = forwardRef(function MyInput({ label, showInput }, ref) {
  return (
    <label>
      {label}
      <Panel isExpanded={showInput}>
        <input ref={ref} />
      </Panel>
    </label>
  );
});