#IntersectionObserver BTS

IntersectionObserver is used to observe the intersection status between the target node and the reference node and the target node and the ancestor node. When the intersection status changes, the corresponding callback is triggered. Based on this, you can monitor whether the target node is exposed/de-exposed.

#Instance method

IntersectionObserver.relativeTo()

Specify the reference node, which is specified based on id.

IntersectionObserver.relativeToViewport()

Specify LynxView as the reference node.

IntersectionObserver.relativeToScreen()

Specify the screen as the reference node.

IntersectionObserver.observer()

Specify the target node and callback. The target node is specified based on id.

IntersectionObserver.disconnect()

Clear the target node and callback, the target node will no longer be observed, and the corresponding callback will not be triggered.

#Example

You can observe changes in the intersection status of the target node and the reference node through the following three steps:

1. Create an IntersectionObserver object and specify a threshold list for intersection state changes
2. Call the relativeTo* method of the IntersectionObserver object to specify the reference node
3. Call the observe method of the IntersectionObserver object to specify the target node and callback
4. Call the disconnect method of the IntersectionObserver object to clear the target node and callback

// 1. Create IntersectionObserver object
const observer = lynx.createIntersectionObserver(this, {
  thresholds: [0, 0.25, 0.5, 0.75, 1.0],
});

// 2. Call the relativeTo method to specify the reference node
observer.relativeTo('#refNode', { left: 10, right: 10 });

// 3. Call the observe method to specify the target node and callback
observer.observe('#targetNode', (res) => {
  console.log('IntersectionObserver: ', JSON.stringify(res));
});

// 4. Call the disconnect method to clear the target node and callback
observer.disconnect();

#Precautions

• When using relativeTo and observe methods, you need to pay attention to the calling timing and ensure that the reference node and target node have been created when calling. Otherwise, the observation will be invalid, that is, the corresponding callback will never be triggered.
• On Android, child nodes of a horizontally scrolling scroll-view do not trigger callbacks while scrolling. Set flatten to false on the child node to trigger them.

#Compatibility