Interface ObservableXYData<T>

Add callback function to be triggered when specified event is fired.

 // Example syntax
 object.addEventListener('click', (event) => {
     console.log(event)
 })

Some classes also report extra information about the interacted object with the second parameter:

 // Most series share information about interacted data point
 series.addEventListener('click', (event, info) => {
     console.log(info)
 })

Optional third parameter allows registering event handlers that will automatically remove themselves after first trigger:

 // Example this listener will only fire once
 object.addEventListener('click', (event) => {})

Each class has its own list of supported events. Some events are from HTML standard (click, pointerdown, etc.), while others are own events from LightningChart JS (dispose, resize, etc.)

To find what events are available, you can try following:

• If your development environment has TypeScript enabled, just write addEventListener and see what possible event types the IDE suggests. These APIs are strongly typed, and even the callback event will be correctly typed.
• Otherwise, open the class section in API documentation and check out which interface K type parameter extends.

Remove event listener added using addEventListener. The expected argument should be the exact same callback function that was supplied using addEventListener:

 // Basic example syntax
 const listener = () => {}
 obj.addEventListener('click', listener)
 obj.removeEventListener('click', listener)

 // Basic boilerplate of custom interaction when user drags on an object
 obj.addEventListener('pointerdown', (eventDown) => {
     let prevCoord = eventDown
     const handlePointerMove: LCJSInteractionEventListener<'pointermove'> = (eventMove) => {
         const delta = { x: eventMove.clientX - prevCoord.clientX, y: eventMove.clientY - prevCoord.clientY }
         prevCoord = eventMove
         console.log(delta, eventMove.clientX, eventMove.clientY)
     }
     const handlePointerUp: LCJSInteractionEventListener<'pointerup'> = (eventUp) => {
         window.removeEventListener('pointermove', handlePointerMove)
         window.removeEventListener('pointerup', handlePointerUp)
     }
     window.addEventListener('pointermove', handlePointerMove)
     window.addEventListener('pointerup', handlePointerUp)
 })