Editor’s Note: This post was last updated on 31 March 2023 to reflect updates to React. This update also includes new sections on why forwardRef is important, how to use forwardRef with TypeScript, and when to use forwardRef in React.
In this tutorial, we will go over the concept of forwarding refs in React and understand how it helps us manage interactions with the DOM. For a more engaging experience, we’ll cover how to create refs, attach created refs to DOM elements and classes, use the forwardRef method, etc.
It is also worth noting that we will often reference the docs page to build on the existing information and prove our concepts with relatable real life examples and snippets to be hosted on CodeSandbox.
Jump ahead:
- What is
forwardRefin React? - How do refs work in React?
- When to use refs in React
- Working with refs in class components
- Forwarding refs in React using
forwardRef - How to use
forwardRefwith TypeScript - When not to use refs in React
What is forwardRef in React?
In React, forwardRef is a utility function that passes down a ref through a component to one of its children. This is particularly useful when you need to access a DOM element or component instance directly in a parent component, but the desired child element is wrapped by a higher-order component or a component that doesn’t expose the ref by default.
forwardRef takes a functional component as its argument and returns a new component with a forwarded ref attribute. This allows you to directly access the underlying child DOM node or instance from a parent component using the ref.
Why is forwardRef important?
forwardRef is important in React because it allows for more flexible and efficient component composition. When working with complex applications, there are cases where you need direct access to a child component’s DOM element or instance from a parent component. However, React’s default behavior doesn’t always allow this, especially when dealing with higher-order components (HOCs) or wrapper components.
By using forwardRef, you can pass a reference from a parent component to a child component, even if that child component is wrapped inside another component. This enables the parent component to interact with the child’s DOM element or instance directly.
How do refs work in React?
To understand ref forwarding, we must first understand what refs are. Refs are a way to access and interact with a DOM element directly. Refs allow you to bypass the typical React data flow and perform actions not achievable with props and state alone.
They are often used for tasks like setting focus on an input field, measuring the dimensions of an element, or triggering animations. For instance, you can use refs to give focus on an input field when a button is clicked:
import * as React from "react";
import ReactDOM from "react-dom";
export default function App() {
const ref = React.useRef();
function focus() {
ref.current.focus();
}
return (
<div className="App">
<input ref={ref} placeholder="my input" />
<button onClick={focus}>Focus</button>
</div>
);
}
const rootElement = document.getElementById("root");
ReactDOM.render(<App />, rootElement);
Similarly, we could use JavaScript to achieve a similar effect. However, it is not recommended to do this, and it is even marked as a bad practice to access DOM directly when using React. The vanilla JavaScript equivalent to focusing an element could be:
document.getElementById('myInput).focus()
When to use refs in React
There are many refs in React that can be pointed to using forwardRef. In React, it’s generally recommended to use props and state to manage your component data flow. However, there are some situations where using refs can be helpful or even necessary. Here are some common use cases for refs in React:
- Managing focus, text selection, or media playback: Refs can be used to manage focus on form elements, select text in an input or text area, or control media playback for audio or video elements
- Triggering animations: If you need to trigger animations using external libraries like GSAP or Anime.js, you might need a direct reference to a DOM element, which can be achieved using refs
- Integrating with third-party DOM libraries: When using third-party libraries that require direct access to DOM elements, refs can be useful for providing the necessary access
- Measuring the dimensions or position of elements: Refs can help you measure the size, position, or scroll position of an element. This can be useful for tasks like implementing a custom scrollbar, creating tooltips, or building responsive components
While refs are a powerful tool, they should be used sparingly and only when necessary. Excessive use of refs can lead to code that is harder to understand and maintain. Always opt to use props and state for data flow in React components when possible.
Working with refs in class components
In this section, we will focus specifically on working with refs in class components. Although React has moved towards functional components with React Hooks, it is still important to understand how to manage refs in class components, as they remain prevalent in many existing projects. We will cover the process of creating, attaching, and using refs in class components, along with examples that illustrate common use cases. This knowledge will enable you to use refs effectively in class components and facilitate a smoother transition to functional components and Hooks when needed.
Creating refs in React
To create a ref, React provides a function called React.createRef. Once created, they can be attached to React elements via the ref attribute. When a component is constructed, refs get assigned to instance properties of that component, ensuring that they can be referenced anywhere in the component. Here’s what that looks like:
class MyComponent extends React.Component {
constructor(props) {
super(props);
this.newRef = React.createRef(); //newRef is now available for use throughout our component
}
...
}
At this point, we have created a Ref called newRef. To use this Ref in our component, we simply pass it as a value to the ref attribute like this:
class MyComponent extends React.Component {
...
render() {
return <div ref={this.myRef} />;
}
}
Here, we’ve attached the Ref and passed in the newRef as its value. As a result, we now have the ability to update this without changing the component’s state.
Attaching refs
In this section, we will discuss the process of attaching refs in React. Attaching refs in React is the process of relating a ref with a DOM element for direct DOM manipulation. This step is crucial in order to effectively work with refs and employ their potential in various use cases, such as managing focus, measuring element dimensions, or triggering animations.
We already covered how to create refs with createRef, so now we will relate it to a DOM element by using the ref prop:
<div ref={this.myRef} />
And, finally, when we are ready to access the DOM element later on the component lifecycle, we can do something like this:
const divWidth = this.myRef.current.offsetWidth;
Let’s see this behavior with a complete example where we are going to attach a reference to an HTML video element and use React buttons to play and pause the video using the native HTML5 APIs of the video element:
import ReactDOM from "react-dom";
import React, { Component } from "react";
export default class App extends Component {
constructor(props) {
super(props);
this.myVideo = React.createRef();
}
render() {
return (
<div>
<video ref={this.myVideo} width="320" height="176" controls>
<source
src="https://res.cloudinary.com/daintu6ky/video/upload/v1573070866/Screen_Recording_2019-11-06_at_4.14.52_PM.mp4"
type="video/mp4"
/>
</video>
<div>
<button
onClick={() => {
this.myVideo.current.play();
}}
>
Play
</button>
<button
onClick={() => {
this.myVideo.current.pause();
}}
>
Pause
</button>
</div>
</div>
);
}
}
const rootElement = document.getElementById("root");
ReactDOM.render(<App />, rootElement);
Here, we used ref to pause and play our video player by calling the pause and play methods on the video. When the pause or play button is clicked, the function will be called on the video player without a re-render.
Using refs with function components
Refs cannot be attached to function components. Although, we can define refs and attach them to either DOM elements or class components. The bottom line is that function components do not have instances, so you can’t reference them.
However, if you must attach a ref to a function component, the official React team recommends converting the component to a class, just like you would do when you need lifecycle methods or state.
Conditional refs
Aside from passing the default ref attribute, we can also pass functions to set refs. The major advantage of this approach is that you have more control over when refs are set and unset. That is possible because it allows us to determine the state of the ref before certain actions are fired. Consider this snippet from the documentation page below:
class CustomTextInput extends React.Component {
constructor(props) {
super(props);
this.textInput = null;
this.setTextInputRef = element => {
this.textInput = element;
};
this.focusTextInput = () => {
// Focus the text input using the raw DOM API
if (this.textInput) this.textInput.focus();
};
}
componentDidMount() {
this.focusTextInput();
}
render() {
return (
<div>
<input
type="text"
ref={this.setTextInputRef}
/>
<input
type="button"
value="Focus the text input"
onClick={this.focusTextInput}
/>
</div>
);
}
}
Instead of defining the refs in the constructor, we set the initial value to null. The benefit of this approach is that textInput will not reference a node until the component is loaded (when the element is created).
Forwarding refs in React using forwardRef
When a child component needs to reference its parent component’s current node, the parent component needs a way to send down its ref to the child. The technique is called ref forwarding.
Ref forwarding is a technique for automatically passing a ref through a component to one of its children. It’s very useful when building reusable component libraries. forwardRef is a function used to pass the ref to a child component.
Let’s take an example of a new library with an InputText component that will provide a lot of functionality, though, for now, we’ll keep it simple:
const InputText = (props) => (
<input {...props} />
));
The InputText() component will tend to be used throughout the application in a similar manner as a regular DOM input, therefore accessing its DOM node may be unavoidable for managing focus, selection, or animations related to it.
In the example below, other components in the application have no access to the DOM input element generated by the InputText() component and are, thus, restricting some of the operations we have already foreseen we would need to meet our application requirements, such as controlling the focus of the input programmatically.
Here is when React.forwardRef enters to obtain a ref passed as props, and then forwards it to the DOM input that it renders, as shown below:
const InputText = React.forwardRef((props, ref) => (
<input ref={ref} {...props} />
));
Now that our component supports forwardRef, let’s use it in the context of our application to build a button that will automatically focus the input when it’s clicked. The code looks as follows:
import * as React from "react";
import ReactDOM from "react-dom";
const InputText = React.forwardRef((props, ref) => (
<input ref={ref} {...props} />
));
export default function App() {
const ref = React.useRef();
function focus() {
ref.current.focus();
}
return (
<div className="App">
<InputText ref={ref} placeholder="my input" />
<button onClick={focus}>Focus</button>
</div>
);
}
const rootElement = document.getElementById("root");
ReactDOM.render(<App />, rootElement);
In the code above, we defined a ref in the component that needs the ref and passed it to the button component. React passed the ref through and forwarded it down to <input ref={ref}> by specifying it as a JSX attribute. When the ref was attached, ref.current pointed to the <input> DOM node.
Learn more →The second ref argument in the InputRef component only existed when you defined a component with React.forwardRef call. Regular function or class components didn’t receive the ref argument, and ref was not available in props. Ref forwarding is not limited to DOM components; you can forward refs to class component instances.
How to use forwardRef with TypeScript
TypeScript is a JavaScript subset that offers the benefits of static typing, enhanced tooling, and improved maintainability, leading to more robust and reliable code in your JavaScript applications. forwardRef, as part of the React library, provides full support for TypeScript, though to maximize its benefits, the code we write should also be strongly typed.
Say, for example, that you have a function component that uses forwardRef to expose the DOM reference to an HTML input element. This functional component also has its own props declared with their types. When using forwardRef in such an example, we’ll have to take care of strongly typing the component to avoid errors and improve code readability. One way to do this is by using generic types in forwardRef; here’s an example:
type IInputProps = {
label: string;
};
const InputText = React.forwardRef<HTMLInputElement, IInputProps>((props, ref) => (
<div>
<span>{props.label}</span>
<input ref={ref} placeholder="your input goes here..." />
</div>
)
);
As we can see in the code, it is important to specify the type of the Ref element and the props. Another common way to declare the same component is to assign the type directly in the parameters of the callback function, as follows:
type IInputProps = {
label: string;
};
const InputText = React.forwardRef((props: IInputProps, ref: React.Ref<HTMLInputElement>) => (
<div>
<span>{props.label}</span>
<input ref={ref} placeholder="your input goes here..." />
</div>
)
);
In this case, when passing the type for the ref param, we need to make sure we are wrapping the element type with React.Ref. Both ways to declare the component are valid, and there is no argument for one over the other. It’s up to the developer’s style, and in my case, I prefer the first way because I believe it looks cleaner.
Similarly, when working on the parent component, we need to specify the reference type, and it needs to match the one used in forwardRef. To do that, you can use generic types when using useRef as follows:
const ref = React.useRef<HTMLInputElement>(null);
Failing to do so may trigger errors when trying to use methods and properties from the element, as we can see in the image below:
When not to use refs in React
In React, refs are a powerful feature that allows developers to interact with DOM elements and components directly. However, there are certain situations where using refs may not be the best approach. Here are a few:
Unnecessary DOM manipulation
React encourages a declarative approach to building UIs, so you should avoid using refs for direct DOM manipulation unless absolutely necessary. Use component state and props to handle most UI updates
Overusing refs in stateless components
Functional components are often meant to be simple and stateless. If you find yourself using multiple refs in a functional component, consider if it could be split into smaller components or if state management should be lifted to a higher-level component
Using refs for data flow
Refs should not be used as a replacement for state management or prop passing. Data should primarily flow through component props, and when necessary, state management libraries like Redux or React’s Context API can be used
Using refs in place of controlled components
In form elements, use controlled components (by setting the value and handling input changes through state and event handlers) whenever possible. Refs should only be used for uncontrolled components when there is a specific need for direct access to the DOM element
Accessing child components’ internal state
Refs should not be used to reach into a child component’s internal state or methods. Instead, use callback functions or other state management patterns to communicate between parent and child components
Remember, refs should generally be used sparingly and only when necessary. In many cases, React’s inbuilt mechanisms for state and prop management are more appropriate for handling component interaction and updates.
Conclusion
Refs in React are a powerful tool that enables direct access to DOM nodes and thus open a whole new spectrum of methods and options to build more performant, feature-rich and clean components. However, accessing DOM directly is often seen as a bad practice in React, and for a reason, when used improperly, it can turn all its benefits into real problems.
As a general rule, it should be avoided and used only under very specific circumstances and with a thorough examination. In this tutorial, we introduced the topic of refs and ref forwarding, we looked at a few use cases and we built the code using function and class components. To read more about refs check out the docs here. Thanks for reading!
LogRocket: Full visibility into your production React apps
Debugging React applications can be difficult, especially when users experience issues that are hard to reproduce. If you’re interested in monitoring and tracking Redux state, automatically surfacing JavaScript errors, and tracking slow network requests and component load time, try LogRocket.
LogRocket combines session replay, product analytics, and error tracking – empowering software teams to create the ideal web and mobile product experience. What does that mean for you?
Instead of guessing why errors happen, or asking users for screenshots and log dumps, LogRocket lets you replay problems as if they happened in your own browser to quickly understand what went wrong.
No more noisy alerting. Smart error tracking lets you triage and categorize issues, then learns from this. Get notified of impactful user issues, not false positives. Less alerts, way more useful signal.
The LogRocket Redux middleware package adds an extra layer of visibility into your user sessions. LogRocket logs all actions and state from your Redux stores.
Modernize how you debug your React apps — start monitoring for free.
In general good information, but about forwardRef info, very disappointing. It is almost a copy/paste from the react documentation. I was looking to understand forwardRef better.
document.getElementById(‘myInput).focus()
A ‘single quote’ is missing after myInput.
Good catch, thanks