What is the intersection observer?
An Intersection Observer is a browser API that provides a way to observe the visibility and position of a DOM element relative to the containing root element or viewport. Some common use cases of this API include lazy-loading images on scroll, implementing infinite scrolling, and animations.
How do you use intersection observer in react?
Create the options object with the same values as the image. Add the react hook useEffect and create an observer contructor using the callback function and the options we just created before, it’s optional in our case but you can return a cleanup function to unobserve our target when the component unmounts.
What are entries in intersection observer?
A single entry You can refer to each element as an entry by the observer. An IntersectionObserverEntry object holds intersection information for a given target. The information can be something like the ratio of the intersection, the time at which the intersection happened, or the dimensions of the target and so on.
Can you have multiple intersection observers?
3 Answers. Modifying Ruslan’s answer a little because in his answer, multiple Intersection Observer objects are being created. It is possible to observe multiple elements using the same observer by calling . observe() on multiple elements.
What is intersection observer Javascript?
The Intersection Observer API provides a way to asynchronously observe changes in the intersection of a target element with an ancestor element or with a top-level document’s viewport.
Is intersecting intersection observer?
Intersection Observer observes the “intersection” (i.e. the passing across) of an element through one of its ancestor elements or the area on screen where the page is visible ( aka the viewport). It’s sort of like watching a train pass through a station.
How do you use intersection observer for infinite scroll?
To do an infinite scroll, we need to increment page number count when last element of the list is visible to user. This will be done by intersection observer. Our intersection observer will observe if the last element is visible or not, if it is, we will increment the page number by 1.
What is root in intersection observer?
The IntersectionObserver interface’s read-only root property identifies the Element or Document whose bounds are treated as the bounding box of the viewport for the element which is the observer’s target. If the root is null , then the bounds of the actual document viewport are used.
What is IntersectionObserver in Javascript?
The IntersectionObserver interface of the Intersection Observer API provides a way to asynchronously observe changes in the intersection of a target element with an ancestor element or with a top-level document’s viewport. The ancestor element or viewport is referred to as the root.
What is intersection observer in JS?
The Intersection Observer API lets code register a callback function that is executed whenever an element they wish to monitor enters or exits another element (or the viewport), or when the amount by which the two intersect changes by a requested amount.
What is rootMargin IntersectionObserver?
The IntersectionObserver interface’s read-only rootMargin property is a string with syntax similar to that of the CSS margin property. Each side of the rectangle represented by rootMargin is added to the corresponding side in the root element’s bounding box before the intersection test is performed.
What is Intersectionobserver react?
What is Intersection Observer API in JavaScript?
You are looking to know Intersection Observer API in depth. Intersection Observer is a new API that can be used to detect intersection of a DOM element with a parent DOM element, or with the browser screen. By detecting intersection you can check the visibility of the element with respect to another element.
What is the use case of Intersection Observer?
Using Intersection Observer we can observe the visibility change of an element (target) in the viewport (screen visible area). The most important use case of Intersection Observer is Lazy Loading…
What is interintersection observer?
Intersection Observer is a new API that can be used to detect intersection of a DOM element with a parent DOM element, or with the browser screen. By detecting intersection you can check the visibility of the element with respect to another element. A simple example can be detecting whether an element is visible in the window screen or not.
How to watch for intersection of elements relative to root?
To watch for intersection relative to the root element, specify null. Whether you’re using the viewport or some other element as the root, the API works the same way, executing a callback function you provide whenever the visibility of the target element changes so that it crosses desired amounts of intersection with the root.