Display digital clock using React

by vsasikalabe Updated: Jan 24, 2023

Create a Digital Clock using React using class Date. When Digital Clock is mounted a Digital Clock should update the state variable time with current Time. This Digital Clock should update the time variable regularly at an interval of 1 sec.The componentDidMount() method allows us to execute the React code when the component is already placed in the DOM (Document Object Model). This method is called during the Mounting phase of the React Life-cycle i.e after the component is rendered.The componentWillUnmount() method allows us to execute the React code when the component gets destroyed or unmounted from the DOM (Document Object Model). This method is called during the Unmounting phase of the React Life-cycle i.e before the component gets unmounted.The clearInterval() method clears a timer set with the setInterval() method.

Preview of the output that you will get on running this code from your IDE.

Code:

In this solution we use the React library.

How to display working digital clock using React

JavaScriptLines of Code : 30License : CC BY-SA 4.0

class ClockFunction extends React.Component {

    constructor() {
        super();
        this.state = { time: new Date() }; // initialise the state
    }

    componentDidMount() { // create the interval once component is mounted
        this.update = setInterval(() => {
            this.setState({ time: new Date() });
        }, 1 * 1000); // every 1 seconds
    }

    componentWillUnmount() { // delete the interval just before component is removed
        clearInterval(this.update);
    }

    render() {
        const { time } = this.state; // retrieve the time from state

        return (<div>
            <h1>Digital Clock</h1>
            <h2>
                {/* print the string prettily */}
                {time.toLocaleTimeString()}
            </h2>
        </div>);
    }
}

Instructions

Follow the steps carefully to get the output easily.

Install the Node.js and React on your IDE(preferable Visual Studio Code).
Create React Application using npx create-react-app foldername.
cd foldername.
Open the folder in IDE.
Copy the code using "copy" button above and paste it in App.js file(remove the earlier code from App.js).
Import React library.
Add export default ClockFunction to the last line of the code.
Open the terminal from IDE.
npm start to run the file.

I hope you found this useful. I have added the link to dependent libraries, version information in the following sections.

I found this code snippet by searching for Display digital clock using React in kandi. You can try any such use case!

Environment Tested

I tested this solution in the following versions. Be mindful of changes when working with other versions.

The solution is created in VS Code 1.73.1 version.
The solution is tested on Nodejs 16.14.2 version.
react 18.2.0 version.

Using this solution, we are able to Display digital clock using React with simple steps. This process also facilities an easy way to use, hassle-free method to create a hands-on working version of code which would help us to Display digital clock using React