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Digital Clock using React

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by Abdul Rawoof A R dot icon Updated: Feb 16, 2023

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In React, a digital clock is an alternative to a traditional analog clock, and this type of clock shows numbers to display the current time in a digital format on the screen, such as on the phone, watch, or alarm clock.


We are using useState and useEffect Hooks, useState hook is used for storing variables that are part of our application's state. It will change as the user interacts with our website, and the useEffect hook allows components to react to lifecycle events such as mounting to the DOM, re-rendering, and unmounting. React is good for creating popular real-time applications like Facebook, DigitalClock, and Messenger. setTime() method is used to set the date object to the time represented by several milliseconds. To get the current data to time new Data() object is used to get the current date. setInterval() method is used to offer window and worker interfaces, repeatedly call a function, or execute a code snippet, and with a fixed time delay between each call, identifying the interval uniquely that returns an interval ID.

Here is an example of how you can implement a Digital Clock using React:

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

Code

In this solution we're using React library.

React having troubles creating a ticking clock that can change time manually

JavaScriptdotLines of Code : 54dotLicense : Strong Copyleft (CC BY-SA 4.0)

useEffect(() => {
  const tickClock = setInterval(() => {
    updateTimeInfo(SECOND_IN_MS);
  }, SECOND_IN_MS);

  return () => clearInterval(tickClock);
}, []);

const updateTimeInfo = (addedTime) => {
  setTimeDate((timeDate) => addTime(timeDate, addedTime));
  //other info omitted, won't affect the code
};

const SECOND_IN_MS = 1000;
const HOUR_IN_MS = 1000 * 60 * 60;

const addTime = (date, time) => new Date(date.getTime() + time);

const Clock = () => {
  const [timeDate, setTimeDate] = useState(addTime(new Date(), SECOND_IN_MS));

  const updateTimeInfo = (addedTime) => {
    setTimeDate((timeDate) => addTime(timeDate, addedTime));
    //other info omitted, won't affect the code
  };

  useEffect(() => {
    const tickClock = setInterval(() => {
      updateTimeInfo(SECOND_IN_MS);
    }, SECOND_IN_MS);

    return () => clearInterval(tickClock);
  }, []);

  return (
    <>
      <span>
        {timeDate.toLocaleTimeString([], {
          hour: "2-digit",
          hour12: true,
          minute: "2-digit",
          second: "2-digit"
        })}
      </span>
      <button type="button" onClick={() => updateTimeInfo(HOUR_IN_MS)}>
        +1 hour
      </button>
      <button type="button" onClick={() => updateTimeInfo(-HOUR_IN_MS)}>
        -1 hour
      </button>
    </>
  );
};

Instructions

Follow the steps carefully to get the output easily.

  1. Install the Node.js and React on your IDE(preferable Visual Studio Code).
  2. Create React Application using npx create-react-app foldername.
  3. cd foldername.
  4. Open the folder in IDE.
  5. Copy the code using "copy" button above and paste it in app.js file(remove the earlier code from app.js).
  6. Import React, useState and useEffect in app.js file.
  7. Open the terminal from IDE.
  8. npm start to run the file.


You can also refer this url 'DEMO' for getting the above output.

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 '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.

  1. The solution is created in Visual Studio Code 1.73.1.
  2. The solution is tested on node v18.12.1 and npm v8.19.2.
  3. React version-18.2.0.


Using this solution, we are able to create 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 create digital clock using React.

Dependent Library

reactby facebook

JavaScript doticonstar image 209050 doticonVersion:v18.2.0doticon
License: Permissive (MIT)

The library for web and native user interfaces

Support
    Quality
      Security
        License
          Reuse

            reactby facebook

            JavaScript doticon star image 209050 doticonVersion:v18.2.0doticon License: Permissive (MIT)

            The library for web and native user interfaces
            Support
              Quality
                Security
                  License
                    Reuse

                      You can also search for any dependent libraries on kandi like 'react'.

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