vue-visibility-sensor

Vue Visibility Sensor

Sensor component for Vue that notifies you when it goes in or out of the window viewport.

Inspired by React Visibility Sensor

Install

npm install vue-visibility-sensor

This component is recommended to use in Vue-cli SPA project. Because it doesn't build as any bundle like AMD or UMD.

It's just a single file component.

Example

Try building an example yourself locally, here's another:

View the example

To run the example locally:

• npm run example
• open example/index.html in a browser

General usage goes something like:

const VisibilitySensor = require('vue-visibility-sensor');

// with children
new Vue({
  components: {
    VisibilitySensor,
  },
  template: `
    <VisibilitySensor @change="onChange">
      <div>...optional content goes here...</div>
    </VisibilitySensor>
  `,
  methods: {
    onChange(isVisible) {
      console.log('Element is now %s', isVisible ? 'visible' : 'hidden');
    }
  }
});

// without children
new Vue({
  components: {
    VisibilitySensor,
  },
  template: `
    <VisibilitySensor @change="onChange">
    </VisibilitySensor>
  `,
  methods: {
    onChange(isVisible) {
      console.log('Element is now %s', isVisible ? 'visible' : 'hidden');
    }
  }
});

Event

• change: the event name emitted from sensor whenever the element changes from being within the window viewport or not. Event name is 'change', all in lower case. Function is called with 1 argument (isVisible: boolean)

Props

Name	Default Value	Description
active	true	boolean flag for enabling / disabling the sensor. When active !== true the sensor will not fire the onChange callback.
partialVisibility	false	consider element visible if only part of it is visible. Also possible values are - 'top', 'right', 'bottom', 'left' - in case it's needed to detect when one of these become visible explicitly.
offset	{}	with offset you can define amount of px from one side when the visibility should already change. So in example setting offset={{top:10}} means that the visibility changes hidden when there is less than 10px to top of the viewport. Offset works along with partialVisibility
minTopValue	0	consider element visible if only part of it is visible and a minimum amount of pixels could be set, so if at least 100px are in viewport, we mark element as visible.
intervalCheck	true	when this is true, it gives you the possibility to check if the element is in view even if it wasn't because of a user scroll
intervalDelay	100	integer, number of milliseconds between checking the element's position in relation the the window viewport. Making this number too low will have a negative impact on performance.
scrollCheck	false	by making this true, the scroll listener is enabled.
scrollDelay	250	the debounce rate at which the check is triggered. Ex: 250ms after the user stopped scrolling.
scrollThrottle	-1	by specifying a value > -1, you are enabling throttle instead of the delay to trigger checks on scroll event. Throttle supercedes delay.
resizeCheck	false	by making this true, the resize listener is enabled. Resize listener only listens to the window.
resizeDelay	250	is the debounce rate at which the check is triggered. Ex: 250ms after the user stopped resizing.
resizeThrottle	-1	by specifying a value > -1, you are enabling throttle instead of the delay to trigger checks on resize event. Throttle supercedes delay.
delayedCall	false	if is set to true, wont execute on page load ( prevents react apps triggering elements as visible before styles are loaded )
containment	window	element to use as a viewport when checking visibility. Default behaviour is to use the browser window as viewport.
children	<span></span>	can be a template or vue component

It's possible to use both intervalCheck and scrollCheck together. This means you can detect most visibility changes quickly with scrollCheck, and an intervalCheck with a higher intervalDelay will act as a fallback for other visibility events, such as resize of a container.

Thanks

Special thanks to Josh Johnston

License

MIT

Changelog

0.3.0

• Refactor the template string into render function.