How to detect if user triggered scroll event vs window.scroll?

Question

I use window.addEventListener to handle scrolling events.

componentDidMount() {
  window.addEventListener("scroll", this.handleScroll)
}

I would like to disable that event handler when scrolling is triggered programatically by window.scroll vs user.

A similar case for button click https://stackoverflow.com/questions/14794380/detect-if-button-click-real-user-or-triggered-by-a-script — Asutosh, Aug 15 '20 at 13:17

score 0 · Answer 1 · answered Aug 15 '20 at 13:19

0

Here's a little useful trick...

if(event.isTrusted){

 // human gesture

} else {

// automated

}

answered Aug 15 '20 at 13:19

user4723924

Thanks! Promising but given `window.scroll` is called by the user, `event.isTrusted` always returns `true`. Perhaps I am missing something? – sunknudsen Aug 15 '20 at 13:22
This isTrusted gives true if some one scroll it by schanging the scrollTop. So this has false positive: https://jsfiddle.net/asutosh/rf9zakym/11/ – Asutosh Aug 15 '20 at 13:23
See https://stackoverflow.com/questions/36656858/why-does-calling-window-scroll-give-a-trusted-event – sunknudsen Aug 15 '20 at 13:25
Something like window.scrollTo(100,0) is not a human gesture. – user4723924 Aug 15 '20 at 13:25
Agreed, but it is triggered by a human so I believe it would register `isTrusted` as `true`. – sunknudsen Aug 15 '20 at 13:28
Well then you'll have to set up a global flag and set it as required and where required. – user4723924 Aug 15 '20 at 13:32
Sadly, looks like few elegant options exist to distinguish between these events. – sunknudsen Aug 15 '20 at 13:37
Btw, I see you are new to StackOverflow. Not all people ruthlessly downvote answers (I know it can be demotivating). Thanks for trying to help and welcome! – sunknudsen Aug 15 '20 at 13:45

1 Answers1