react-scrollwatch

Motivation

There are a couple of existing libraries for handling scroll events: scrollwatch and react-component-visibility. However neither of these worked well in modern react projects.

react-scrollwatch is a simple higher order component (HOC) that makes reacting to when a components shows up in the viewport.

Browser only

This module depends on a browser environment with document and window. Other environments such as those available through React Native is not currently supported.

Install

npm i -S react-scrollwatch

Usage

react-scrollwatch relies on nwb. This is mainly for packaging into various types of npm-ready modules (compatible with UMD, CommonJS, ES5, and ES6). Run the example to see this component in action:

git clone https://github.com/vuldin/react-scrollwatch.git
cd react-scollwatch
npm i -g nwb
npm i
npm start

Open http://localhost:3000 and scroll down the page to see a div change background color when in view.

Properties

All properties are optional.

• shownPercent (default: '50%'): percentage of the div that needs to be shown from either side before being considerd 'shown'
• throttle (default: 250): milliseconds to wait between listening for one of the following listeners:
  1. visibilitychange (on document)
  2. scroll (on document)
  3. resize (on window)
• onShown (default: function undefined): if defined this function will be passed the JSON version of the style from the wrapped component once it is considered visible.
• onHidden (default: function undefined): if defined this function will be passed the JSON version of the style from the wrapped component once it is considered hidden.
• style properties (default: none): Pass any css styles you wish as properties to this higher order component... they will be applied as inline styled to the wrapped component.

Guidelines

• This HOC must wrap a React component. Normal elements will result in an error.

Testing

While testing is built in to this project (thanks to nwb!) I have not yet created tests. Check back later!