How to submit a form using Enter key in react.js?

Question

Change <button type="button" to <button type="submit". Remove the onClick. Instead do <form className="commentForm" onSubmit={this.onFormSubmit}>. This should catch clicking the button and pressing the return key.

onFormSubmit = e => {
  e.preventDefault();
  const { name, email } = this.state;
  // send to server with e.g. `window.fetch`
}

...

<form onSubmit={this.onFormSubmit}>
  ...
  <button type="submit">Submit</button>
</form>

It's been quite a few years since this question was last answered. React introduced "Hooks" back in 2017, and "keyCode" has been deprecated.

Now we can write this:

  useEffect(() => {
    const listener = event => {
      if (event.code === "Enter" || event.code === "NumpadEnter") {
        console.log("Enter key was pressed. Run your function.");
        event.preventDefault();
        // callMyFunction();
      }
    };
    document.addEventListener("keydown", listener);
    return () => {
      document.removeEventListener("keydown", listener);
    };
  }, []);

This registers a listener on the keydown event, when the component is loaded for the first time. It removes the event listener when the component is destroyed.

Use keydown event to do it:

   input: HTMLDivElement | null = null;

   onKeyDown = (event: React.KeyboardEvent<HTMLDivElement>): void => {
      // 'keypress' event misbehaves on mobile so we track 'Enter' key via 'keydown' event
      if (event.key === 'Enter') {
        event.preventDefault();
        event.stopPropagation();
        this.onSubmit();
      }
    }

    onSubmit = (): void => {
      if (input.textContent) {
         this.props.onSubmit(input.textContent);
         input.focus();
         input.textContent = '';
      }
    }

    render() {
      return (
         <form className="commentForm">
           <input
             className="comment-input"
             aria-multiline="true"
             role="textbox"
             contentEditable={true}
             onKeyDown={this.onKeyDown}
             ref={node => this.input = node} 
           />
           <button type="button" className="btn btn-success" onClick={this.onSubmit}>Comment</button>
         </form>
      );
    }

this is how you do it if you want to listen for the "Enter" key. There is an onKeydown prop that you can use and you can read about it in react doc

and here is a codeSandbox

const App = () => {
    const something=(event)=> {
        if (event.keyCode === 13) {
            console.log('enter')
        }
    }
return (
    <div className="App">
        <h1>Hello CodeSandbox</h1>
        <h2>Start editing to see some magic happen!</h2>
        <input  type='text' onKeyDown={(e) => something(e) }/>
    </div>
);
}

import React, { useEffect, useRef } from 'react';

function Example() {

    let inp = useRef();
    useEffect(() => {
        if (!inp && !inp.current) return;
        inp.current.focus();
        return () => inp = null;
    });

    const handleSubmit = () => {
        //...
    }

    return (
        <form
            onSubmit={e => {
                e.preventDefault();
                handleSubmit(e);
            }}
        >
            <input
                name="fakename"
                defaultValue="...."
                ref={inp}
                type="radio"
                style={{
                    position: "absolute",
                    opacity: 0
                }}
            />
            <button type="submit">
                submit
            </button>
        </form>
    )
}

Enter code here sometimes in popups it would not work to binding just a form and passing the onSubmit to the form because form may not have any input.

In this case if you bind the event to the document by doing document.addEventListener it will cause problem in another parts of the application.

For solving this issue we should wrap a form and should put a input with what is hidden by css, then you focus on that input by ref it will be work correctly.