sonar-js
v1.1.0
Published
A tiny library for detecting when a browser is scrolled to the bottom of a web page.
Downloads
183
Readme
Sonar.js
A tiny library for detecting when a browser is scrolled to the bottom of a web page.
You could use this, for example, on a blog to show a popover when a reader has finished a post, letting them know they can receive new posts by email if they submit their email address.
Installation
yarn add sonar-js
The package comes in three formats: CommonJS, Universal Module Definition, and ECMAScript Module.
| Format | package.json key | Path | |--------|------------------|-------------------| | CJS | main | dist/sonar.js | | UMD | umd:main | dist/sonar.umd.js | | ESM | module | dist/sonar.m.js |
The package is built on-the-fly before publishing to NPM so the dist
folder is not in the repo. If you’d like the built files install it via yarn
or npm
and pluck the file you need out of node_modules/sonar-js/dist/
.
Usage
Create an instance of Sonar
passing in the window
and then call ping
passing in the range to the bottom of the page, a function to call when within range of the bottom and an optional function to call when not within range of the bottom.
When ping
is called one of the callbacks will fire, depending on whether or not the scroll is currently within range of the page bottom. The behavior after that depends on which callbacks are provided.
One callback
var sonar = new Sonar(window)
var withinRangeOfPageBottom = function() {
document.querySelector('.popover').classList.remove('hidden')
}
sonar.ping(600, withinRangeOfPageBottom)
Without a second callback to fire when losing the bottom of the page this is essentially a one-time use. The callback will fire once when finding the bottom of the page and then never fire again, even if you scroll up and back down again.
This is useful for making a permanent change when someone scrolls to the bottom of the page.
Two callbacks
var sonar = new Sonar(window)
var withinRangeOfPageBottom = function() {
document.querySelector('.popover').classList.remove('hidden')
}
var notWithinRangeOfPageBottom = function() {
document.querySelector('.popover').classList.add('hidden')
}
sonar.ping(600, withinRangeOfPageBottom, notWithinRangeOfPageBottom)
With a second callback to fire when losing the bottom of the page this becomes a toggle. The callbacks will only fire once when finding the bottom or losing the bottom. That is, the callbacks will only fire or re-fire when the state changes.
This is useful for making a temporary change when someone scrolls to the bottom of the page and then reversing it when they scroll away from the bottom of the page.
Tests
yarn test
Credit
The icon is Depth Sounder by Toni Bordoy.
Contributing
- Fork it ( https://github.com/brandonweiss/sonar-js/fork )
- Create your feature branch (
git checkout -b my-new-feature
) - Commit your changes (
git commit -am "Add some feature"
) - Push to the branch (
git push origin my-new-feature
) - Create a new Pull Request