Category: JavaScript

Sometimes, we want to detect Ctrl+V, Ctrl+C using JavaScript.

In this article, we’ll look at how to detect Ctrl+V, Ctrl+C using JavaScript.

How to detect Ctrl+V, Ctrl+C using JavaScript?

To detect Ctrl+V, Ctrl+C using JavaScript, we can listen to the keyup and keydown events.

For instance, we write

let ctrlActive = false;
let cActive = false;
let vActive = false;

document.body.addEventListener("keyup", (event) => {
  if (event.key == "Control") ctrlActive = false;
  if (event.code == "KeyC") cActive = false;
  if (event.code == "KeyV") vActive = false;
});

document.body.addEventListener("keydown", (event) => {
  if (event.key == "Control") ctrlActive = true;
  if (ctrlActive == true && event.code == "KeyC") {
    event.preventDefault();
    //...
  }

  if (ctrlActive == true && event.code == "KeyV") {
    event.preventDefault();
    //...
  }
});

to call addEventListener to listen for the keyup and keydown events.

Then we check the keys that are pressed with key and code in the keyup event listeners to set a few flags.

In the keydown listener, we check if ctrl is pressed with ctrlActive and check the key pressed with event.code.

If they’re both pressed, then the key combos are pressed.

Conclusion

To detect Ctrl+V, Ctrl+C using JavaScript, we can listen to the keyup and keydown events.

Sometimes, we want to add a duration to a moment object with moment.js and JavaScript.

In this article, we’ll look at how to add a duration to a moment object with moment.js and JavaScript.

How to add a duration to a moment object with moment.js and JavaScript?

To add a duration to a moment object with moment.js and JavaScript, we can use the add method.

For instance, we write

const travelTime = moment().add(2, "hours").format("hh:mm A");

to call add with 2 and 'hours' to add 2 hours to the current date time and return the new date time.

Then we call format to return a time string with the time.

Conclusion

To add a duration to a moment object with moment.js and JavaScript, we can use the add method.

Sometimes, we want to check if the user can go back in browser history or not with JavaScript.

In this article, we’ll look at how to check if the user can go back in browser history or not with JavaScript.

How to check if the user can go back in browser history or not with JavaScript?

To check if the user can go back in browser history or not with JavaScript, we can call history.back or history.go.

For instance, we write

history.back();

or

history.go(-1);

to go back to the previous page.

Is there’s no previous page, they’ll do nothing.

Conclusion

To check if the user can go back in browser history or not with JavaScript, we can call history.back or history.go.

Sometimes, we want to get the time zone name in JavaScript.

In this article, we’ll look at how to get the time zone name in JavaScript.

How to get the time zone name in JavaScript?

To get the time zone name in JavaScript, we can use the DateTimeFormat constructor.

For instance, we write

console.log(Intl.DateTimeFormat().resolvedOptions().timeZone)

to call resolvedOptions on the DateTimeFormat object and get the timeZone property to get the device’s current time zone.

Conclusion

To get the time zone name in JavaScript, we can use the DateTimeFormat constructor.

Sometimes, we want to transform object to array with Lodash.

In this article, we’ll look at how to transform object to array with Lodash.

How to transform object to array with Lodash?

To transform object to array with Lodash, w e can use the Object.entries method.

For instance, we write

const arr = Object.entries(obj).map(([key, value]) => ({ key, value }));

to get each property of obj as a key-value pair array.

And then we put the key and value into their own array with map to create an array with the key and value properties.

Conclusion

To transform object to array with Lodash, w e can use the Object.entries method.