Category: JavaScript

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React Answers

How to get the scroll position with React?

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Sometimes, we want to get the scroll position with React.

In this article, we’ll look at how to get the scroll position with React.

How to get the scroll position with React?

To get the scroll position with React, we create our own hook.

For instance, we write

import { useEffect, useState } from "react";

export const useWindowScrollPositions = () => {
  const [scrollPosition, setPosition] = useState({ scrollX: 0, scrollY: 0 });

  useEffect(() => {
    const updatePosition = () => {
      setPosition({ scrollX: window.scrollX, scrollY: window.scrollY });
    };

    window.addEventListener("scroll", updatePosition);
    updatePosition();

    return () => window.removeEventListener("scroll", updatePosition);
  }, []);

  return scrollPosition;
};

to listen to the window scroll event with addEventListener.

We set updatePosition as the event listener.

In it, we get the x coordinate of the scroll position with window.scrollX.

And we get the x coordinate of the scroll position with window.scrollY .

We call setPositiion with an object with the values to update scrollPosition.

We remove the event listener with removeEventListener when the component unmounts.

Then we use it by writing

import { useWindowScrollPositions } from "path/to/useWindowScrollPositions";

export const MyComponent = () => {
  const { scrollX, scrollY } = useWindowScrollPositions();

  return (
    <div>
      Scroll position is ({scrollX}, {scrollY})
    </div>
  );
};

We call useWindowScrollPositions to return an object with the scroll coordinates.

Conclusion

To get the scroll position with React, we create our own hook.

Categories
JavaScript Answers

How to add commas or spaces to group every three digits with JavaScript?

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Sometimes, we want to add commas or spaces to group every three digits with JavaScript.

In this article, we’ll look at how to add commas or spaces to group every three digits with JavaScript.

How to add commas or spaces to group every three digits with JavaScript?

To add commas or spaces to group every three digits with JavaScript, we use the toLocaleString method.

For instance, we write

console.log(Number(1234567890.12).toLocaleString());

to call toLocaleString on the number to return a string with the thousands separators included.

Conclusion

To add commas or spaces to group every three digits with JavaScript, we use the toLocaleString method.

Categories
JavaScript Answers

How to sort an array of objects with JavaScript?

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Sometimes, we want to sort an array of objects with JavaScript.

In this article, we’ll look at how to sort an array of objects with JavaScript.

How to sort an array of objects with JavaScript?

To sort an array of objects with JavaScript, we call the array sort method.

For instance, we write

const library = [
  { name: "Steve", course: "WAP", courseID: "cs452" },
  { name: "Rakesh", course: "WAA", courseID: "cs545" },
  { name: "Asad", course: "SWE", courseID: "cs542" },
];

const sortedByNname = library.sort((a, b) => a.name > b.name);

to call library.sort with a function that compares the name values of each entry alphabetically.

It returns an array sorted by the name property value of each object.

Conclusion

To sort an array of objects with JavaScript, we call the array sort method.

Categories
JavaScript Answers

How to write regex for allowing alphanumeric, – , _ and space with JavaScript?

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Sometimes, we want to write regex for allowing alphanumeric, – , _ and space with JavaScript.

In this article, we’ll look at how to write regex for allowing alphanumeric,- , _ and space with JavaScript.

How to write regex for allowing alphanumeric, – , _ and space with JavaScript?

To write regex for allowing alphanumeric, – , _ and space with JavaScript, we use various patterns.

For instance, we write

const re = /^[\w\-\s]+$/;

to define the regex to match alphanumeric, – , _ and space.

\w matches alphanumeric characters and _.

\- matches -,

\s matches spaces.

^ indicates the start of a word.

$ indicates the end of a word.

Conclusion

To write regex for allowing alphanumeric, – , _ and space with JavaScript, we use various patterns.

Categories
JavaScript Answers

How to fix document.getElementByID is not a function error with JavaScript?

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Sometimes, we want to fix document.getElementByID is not a function error with JavaScript.

In this article, we’ll look at how to fix document.getElementByID is not a function error with JavaScript.

How to fix document.getElementByID is not a function error with JavaScript?

To fix document.getElementByID is not a function error with JavaScript, we call getElementById instead of getElementByID.

For instance, we write

const element = document.getElementById("foo");

to call getElementById to get the element with ID foo.

Conclusion

To fix document.getElementByID is not a function error with JavaScript, we call getElementById instead of getElementByID.