Author: John Au-Yeung

Sometimes, we don’t want to render HTML in our React component.

In this article, we’ll look at which values React components can render other than HTML.

Is it Possible to Have React Components that Doesn’t Render HTML?

It’s possible to render values other than HTML in a component.

We can render one of the following values if we don’t a React component to render anything:

false
null
[]
<React.Fragment></React.Fragment>
<></>

We can render false, null, an empty array or an empty fragment in our component.

However, we can’t render undefined.

Conclusion.

It’s possible to render values other than HTML in a component.

We can render false, null, an empty array or an empty fragment in our component.

However, we can’t render undefined.

Sometimes, we want to get input text field values when enter key is pressed in React.

In this article, we’ll look at how to get input text field values when enter key is pressed in React.

Get Input Text Field Values When Enter Key is Pressed in React

To get input text field values when enter key is pressed in React, we can add an event handler for the keypress event into the input.

For instance, we write:

import React from "react";

export default function App() {
  return (
    <input
      onKeyPress={(ev) => {
        if (ev.key === "Enter") {
          ev.preventDefault();
          console.log(ev.target.value);
        }
      }}
    />
  );
}

to set the onKeyPress prop to a function that checks if the enter key is pressed by comparing 'Enter' against ev.key.

We prevent the default server side form submission behavior from happening with ev.preventDefault.

If it’s true. then we get the value that’s typed into the input box with ev.target.value.

Conclusion

To get input text field values when enter key is pressed in React, we can add an event handler for the keypress event into the input.

Sometimes, we want to handle double click events in a React component.

In this article, we’ll look at how to handle double click events in a React component.

Handle Double Click Events in a React Component

To handle double click events in a React component, we can use the regular click event handler and check how many clicks are done with the detail property.

For instance, we write:

import React from "react";

export default function App() {
  const handleClick = (e) => {
    switch (e.detail) {
      case 1:
        console.log("click");
        break;
      case 2:
        console.log("double click");
        break;
      case 3:
        console.log("triple click");
        break;
      default:
        return;
    }
  };

  return <button onClick={handleClick}>Click me</button>;
}

We have the handleClick function that checks the e.detail property to see how many clicks are done.

If it’s 2, then we know the user double clicked.

When we double click on the button, we should see 'double click' logged in the console.

Conclusion

To handle double click events in a React component, we can use the regular click event handler and check how many clicks are done with the detail property.

Sometimes, we want to prevent form submission in a React component.

In this article, we’ll look at how to prevent form submission in a React component.

Prevent Form Submission in a React Component

To prevent form submission in a React component, we should call the event.preventDefault method in our submit event handler function.

For instance, we write:

import React from "react";

export default function App() {
  const onSubmit = (event) => {
    event.preventDefault();
    console.log("submission prevented");
  };

  return (
    <form onSubmit={onSubmit}>
      <input />
      <input type="submit" />
    </form>
  );
}

We have a form with the onSubmit prop set to the onSubmit function so that the onSubmit function is our form’s submit event handler.

In the function, we call event.preventDefault to prevent the default submission behavior.

Therefore, when we click Submit, we see the 'submission prevented' message logged in the console.

Conclusion

To prevent form submission in a React component, we should call the event.preventDefault method in our submit event handler function.

Sometimes, we may encounter the "REACT ERROR th cannot appear as a child of thead. See (unknown) > thead > th" error when developing React apps.

In this article, we’ll look at how to fix the "REACT ERROR th cannot appear as a child of thead. See (unknown) > thead > th" error when developing React apps.

Fix the "REACT ERROR th cannot appear as a child of thead. See (unknown) > thead > th" Error When Developing React Apps

To fix the "REACT ERROR th cannot appear as a child of thead. See (unknown) > thead > th" error when developing React apps, we should make sure that the direct child elements of the table element is a either thead or tr element.

For instance, we write:

import React from "react";

export default function App() {
  return (
    <table>
      <thead>
        <tr>
          <th>name</th>
          <th>age</th>
        </tr>
      </thead>
      <tbody>
        <tr>
          <td>john</td>
          <td>33</td>
        </tr>
        <tr>
          <td>smith</td>
          <td>22</td>
        </tr>
        <tr>
          <td>jane</td>
          <td>24</td>
        </tr>
      </tbody>
    </table>
  );
}

to render a table with the proper headings and rows.

We only put tr elements in the tbody elements.

Conclusion

To fix the "REACT ERROR th cannot appear as a child of thead. See (unknown) > thead > th" error when developing React apps, we should make sure that the direct child elements of the table element is a either thead or tr element.