How To Set Focus On Input After Render In React 16?

When you create a form with React, you might want to set focus on an input element after it is rendered. How do you that?

Let's build a simple React application:

Application screenshot
Figure 1. Our application.

You can find the full source code in this GitHub repository.

Our application is going to render a form with an input field for entering an email address. That's it, nothing else. Once this input element is rendered, we will set focus on it, so that our users could start typing their email address immediately.

Our application will be made of a single component called App, let's create it:


import React, { Component } from "react";

class App extends Component {
  constructor() {
    super();

    this.emailInput = React.createRef();
  }

  componentDidMount() {
    this.emailInput.current.focus();
  }

  render() {
    return (
      <div className="container">
        <div className="row mt-5">
          <div className="col-sm-6 offset-sm-3">
            <form>
              <div className="form-group">
                <label for="email">Email address</label>
                <input
                  type="email"
                  className="form-control"
                  aria-describedby="emailHelp"
                  placeholder="Enter email"
                  ref={this.emailInput}
                />
              </div>
            </form>
          </div>
        </div>
      </div>
    );
  }
}

export default App;

Code snippet 1. App.js

First, let's focus on its render function:


render() {
  return (
    <div className="container">
      <div className="row mt-5">
        <div className="col-sm-6 offset-sm-3">
          <form>
            <div className="form-group">
              <label for="email">Email address</label>
              <input
                type="email"
                className="form-control"
                aria-describedby="emailHelp"
                placeholder="Enter email"
                ref={this.emailInput}
              />
            </div>
          </form>
        </div>
      </div>
    </div>
  );
}

Code snippet 2. App.js

We see three div elements with class names that you might recognize if you're familiar with Bootstrap. Bootstrap helps us create layout for our page.

Inside of the div elements we have a form element that has label and input child elements.

Let's focus on the input element:


<input
  type="email"
  className="form-control"
  aria-describedby="emailHelp"
  placeholder="Enter email"
  ref={this.emailInput}
/>

Code snippet 3. App.js

Now let's think about how setting focus on an input element will work. The first thing to understand is that our input element doesn't exist in the DOM until our App component renders it. And we know that we can't focus on something that doesn't exist!

The first step is to render our input element. React will do this by calling the render method in our App component. Now our input element exists in the DOM, but to focus on it, we need to have a reference to it, don't we? That's where React offers us a prop called ref. We can use this prop on our input element to associate it with a reference that we'll name emailInput:


ref={this.emailInput}

Code snippet 4. App.js

Now when React renders our input element in the DOM it creates a reference to that element and stores it in the this.emailInput reference object. Where does this object come from? We need to create it!

Let's create this.emailInput reference object in our App component's constructor method:


constructor() {
  super();

  this.emailInput = React.createRef();
}

Code snippet 5. App.js

We're calling React.createRef() function to create a new reference object and we're assigning it to our this.emailInput property.

Now you know that to create a reference to an element in the DOM, you need to 1) create a new reference object in component's constructor method using React.createRef() function call and then 2) add a ref prop to the element that we want to reference - passing our reference object to that prop, for example: ref={this.emailInput}.

That's all we need to do to create a reference to an element in the DOM that is rendered by our render method. The next question we should ask ourselves is: where do we access it, how do we access it and how do set focus on it?

Let's answer these questions!

What's the next component's lifecycle method that React calls right after the render method is called? It's componentDidMount method and it's a perfect place for us to access our reference and set a focus on the input element:


componentDidMount() {
  this.emailInput.current.focus();
}

Code snippet 6. App.js

Inside of our componentDidMount method we're calling focus() method on the current property of our this.emailInput reference object:


this.emailInput.current.focus();

Code snippet 7. App.js

The current property is a property that React creates on our this.emailInput reference object - this property stores a reference to our input element in the DOM. Calling .focus() method on the current property will set the focus on our input element.

And now you know how to set focus on input after render in React 16.

Thank you for reading this React tutorial!

Please take a look at the complete source code on GitHub and the live version of our app.

I hope you've enjoyed this tutorial and I would love to hear your feedback in the comments. You can get in touch with me via Twitter and email.

Artemij Fedosejev

Artemij Fedosejev

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