element-resize-detector
Optimized cross-browser resize listener for elements. Up to 37x faster than related approaches (read section 5 of the article).
npm install element-resize-detector
Usage
Include the script in the browser:
<script src="node_modules/element-resize-detector/dist/element-resize-detector.min.js"></script>
This will create a global function elementResizeDetectorMaker
, which is the maker function that makes an element resize detector instance.
You can also require
it like so:
var elementResizeDetectorMaker = require("element-resize-detector");
Create instance
// With default options (will use the object-based approach).
// The object-based approach is deprecated, and will be removed in v2.
var erd = elementResizeDetectorMaker();
// With the ultra fast scroll-based approach.
// This will be the default in v2.
var erdUltraFast = elementResizeDetectorMaker({
strategy: "scroll" //<- For ultra performance.
});
API
listenTo(element, listener)
Listens to the element for resize events and calls the listener function with the element as argument on resize events.
Example usage:
erd.listenTo(document.getElementById("test"), function(element) {
var width = element.offsetWidth;
var height = element.offsetHeight;
console.log("Size: " + width + "x" + height);
});
removeListener(element, listener)
Removes the listener from the element.
removeAllListeners(element)
Removes all listeners from the element, but does not completely remove the detector. Use this function if you may add listeners later and don't want the detector to have to initialize again.
uninstall(element)
Completely removes the detector and all listeners.
Caveats
- If the element has
position: static
it will be changed toposition: relative
. Any unintentionaltop/right/bottom/left/z-index
styles will therefore be applied and absolute positioned children will be positioned relative to the element. - A hidden element will be injected as a direct child to the element.
Credits
Big thanks to Evry sponsoring this project.
This library is using the two approaches (scroll and object) as first described at http://www.backalleycoder.com/2013/03/18/cross-browser-event-based-element-resize-detection/.
The scroll based approach implementation was based on Marc J's implementation https://github.com/marcj/css-element-queries/blob/master/src/ResizeSensor.js.
Please note that both approaches have been heavily reworked for better performance and robustness.
Changelog
1.1.12
- Fixed an issue with embedded WebView's on Android and iOS (when getComputedStyle.width = null). See #74.
- Fixed an issue with unrendered iframe in FireFox. See #68.
1.1.11
- Cleaned up the development build tools.
- Updated dev dependencies.
- Fixed an issue when uninstalling an element, and then calling listenTo in the middle of an old resize event. See #61.
1.1.10
- Fixed so that injected scroll elements are
flex: none
. See #64. - Fixed so that injected object element is not focusable. See #67.
1.1.9
- Fixed uninstall issue when
callOnAdd
being true. Also now removingonAnimationStart
listener when uninstalling. See #49.
1.1.8
- Fixed a compatability issue with
options.idHandler.get
.
1.1.7
- Fixed some rare issues with uninstalling elements while preparing/resizing.
1.1.6
- Fixed an issue with the resize detector changing the dimensions of the target element in some browsers (e.g., IE and FireFox).
1.1.5
- Fixed an issue with having parent elements
dir=RTL
.
1.1.4
- Added extra safety styles to injected elements to make them more resilient to global CSS affecting them.
1.1.3
- Now
uninstall
supports being called with elements that haven't been initialized.uninstall
simply ignores non-erd elements. uninstall
now also supports a collection of elements.
1.1.2
- Fixed so that
uninstall
may be called directly after alistenTo
call. - Fixed a typo in the readme.
- Fixed an invalid test.
1.1.1
- Using
window.getComputedStyle
instead of relying on the method being available in the global scope. This enables this library to be used in simulated browser environments such as jsdom.
1.1.0
- Supporting inline elements
- Event-based solution for detecting attached/rendered events so that detached/unrendered elements can be listened to without polling
- Now all changes that affects the offset size of an element are properly detected (such as padding and font-size).
- Scroll is stabilized, and is the preferred strategy to use. The object strategy will be deprecated (and is currently only used for some legacy browsers such as IE9 and Opera 12).