useIntersectionObserver documentation

Why useIntersectionObserver

The useIntersectionObserver hook simplifies the process of tracking the intersection of an element with its containing element or the viewport in a React application. It provides an easy-to-use interface for observing the visibility of an element.

Installation

To use the useIntersectionObserver hook, simply import it into your React component:

import { useIntersectionObserver } from '@pillar-ui/hooks'

Parameters

The useIntersectionObserver hook takes three parameters:

• ref: React.RefObject<HTMLElement> | Array<React.RefObject<HTMLElement>>: A ref object or an array of ref objects for the element(s) you want to observe the intersection of.
• options: IntersectionObserverOptions: An object containing options for the Intersection Observer. It uses the same options as the IntersectionObserver constructor. You can refer to the Intersection Observer API documentation for more details on the available options.
• callback: IntersectionObserverCallback: A callback function that will be called whenever the intersection of the observed element(s) changes. The callback receives two parameters - entries (an array of IntersectionObserverEntry objects) and observer (the Intersection Observer instance). You can refer to the Intersection Observer API documentation for more details on the IntersectionObserverEntry object.

Usage

To use the useIntersectionObserver hook, call it inside your functional component:

import { useIntersectionObserver } from '@pillar-ui/hooks'

function MyComponent() {
  const ref = useRef<HTMLDivElement>(null)

  const options = { threshold: 0.5, rootMargin: '0px' }

  const callback = (entries, observer) => {
    entries.forEach((entry) => {
      console.log(entry)
    })
  } // Perform actions based on the intersection changes

  useIntersectionObserver(ref, options, callback)

  return <div ref={ref}> Your content here </div>
}

In the example above, the useIntersectionObserver hook is used to track the intersection of a div element with its containing element or the viewport. The ref is assigned to the div element, and the options object configures the threshold and rootMargin for the Intersection Observer. The callback function logs the intersection entries and performs actions based on the intersection changes.

Implementation details

The useIntersectionObserver hook uses the useEffect and useRef hooks from React to create and manage the Intersection Observer. It sets up the observer when the component mounts and disconnects it when the component unmounts. It also updates the observer when the ref, options, or callback changes.

TypeScript Support

The useIntersectionObserver hook is written in TypeScript and provides type definitions for its parameters.

Conclusion

The useIntersectionObserver hook simplifies the process of tracking the intersection of an element with its containing element or the viewport in a React application. By handling the complex logic of setting up and managing the Intersection Observer, this hook allows you to easily observe the visibility of elements and perform actions based on intersection changes.