I needed to get scroll position of div, so I found onScroll event in react documentation, use it in my code and in developer tool found properties that I needed. In documentation I found some words:
Event names: onScroll Properties: number detail DOMAbstractView view Many times I come across a situation when I do not understand why something is written in the documentation and how to use it. Could someone help me and explain what this documentation is saying?
What the documentation is saying is that if you capture the onScroll event, that event object will have at least two properties, including detail and view. For example, this means that you can do:
function onScrollHandler(event) { console.log(event); console.log(event.detail); console.log(event.view); } Specifically, detail will be of type number and view will be of type DOMAbstractView
0 is a number, and as the docs say, event.detail is of type number. What exactly that number means I don't know - link to the docs and maybe I can find it there. And as I said, events has lots of things, and all the docs are saying is that event will have at a minimum the detail and view attributes. The event itself is a complicated thing, giving you lots of information about the event. Go learn about DOM events to see what you can do with them.event.detail will always be 0. It seems to me that the event.detail property actually comes from the mouse event category, which kind of makes sense if you think of a scroll event being an extension of the mouse event, but you don't click to do a scroll so the number of clicks is always 0.