Category: JavaScript

Sometimes, we want to programmatically trigger an input event with JavaScript.

In this article, we’ll look at how to programmatically trigger an input event with JavaScript.

How to programmatically trigger an input event with JavaScript?

To programmatically trigger an input event with JavaScript, we call the dispatchEvent method.

For instance, we write

const event = new Event("input", {
  bubbles: true,
  cancelable: true,
});

element.dispatchEvent(event);

to create a new input event object with the Event object.

We call Event with an object to set the options for the object.

Then we call element.dispatchEvent with event to trigger the event programmatically.

Conclusion

To programmatically trigger an input event with JavaScript, we call the dispatchEvent method.

Sometimes, we want to determine the OS path separator in JavaScript.

In this article, we’ll look at how to determine the OS path separator in JavaScript.

How to determine the OS path separator in JavaScript?

To determine the OS path separator in JavaScript, we can use the path module.

For instance, we write

const path = require("path");
console.log(path.sep);

to use the path.sep property to return the path separator string for the OS that the Node app is running on.

Conclusion

To determine the OS path separator in JavaScript, we can use the path module.

Sometimes, we want to round to whole numbers in JavaScript.

In this article, we’ll look at how to round to whole numbers in JavaScript.

How to round to whole numbers in JavaScript?

To round to whole numbers in JavaScript, we can use some Math methods.

For instance, we write

const ceiling = Math.ceil(num);
const floor = Math.floor(num);
const rounded = Math.round(num);

to call Math.ceil to get the ceiling of number num.

We call Math.floor to get the floorof number num.

And we call Math.round to get num rounded with banker’s rounding.

Conclusion

To round to whole numbers in JavaScript, we can use some Math methods.

Sometimes, we want to invoke a callback at the end of a transition with D3 and JavaScript.

In this article, we’ll look at how to invoke a callback at the end of a transition with D3 and JavaScript.

How to invoke a callback at the end of a transition with D3 and JavaScript?

To invoke a callback at the end of a transition with D3 and JavaScript, we call the on method.

For instance, we write

d3.select("#myid").transition().style("opacity", "0").on("end", myCallback);

to select the element with d3.select.

Then we call transition and style to add a transition to set opacity of the element to 0.

Next, we call on with 'end' and a callback function that runs when the end event is emitted.

Then end event is emitted when the transition is done.

Conclusion

To invoke a callback at the end of a transition with D3 and JavaScript, we call the on method.