Visual Studio代码扩展：如何在拖动鼠标时停止触发onDidChangeTextEditorSelection事件？

Question

I'm currently working on a line parsing extension that performs tasks based on the currently selected line and reparses when the user changes their selection.

It doesn't make sense to update when the user is selecting more than one line, so everything fires inside a block that looks like:

if(editor.selection.isSingleLine){
    // Line Handling Here
}

However, what happens when the user is dragging the mouse to select the text that they want is that the event fires periodically since technically as the user drags over text, they are "selecting" slices of what they intend on selecting on the way there, some of which only consist of the line they started to drag on.

It also parses twice for doubleclick, but that's probably fine because the selected word is on the same line anyways.

For keyboard and commands, it behaves as intended, but I want it to only fire on a single click (re-positioning the cursor) or once the user is done dragging to select.

It may be a non-issue since the last selection will executed last and I could hack something together to use that, but that seems inelegant and may cause extremely poor performance since the line checking would be executed repeatedly.

EDIT: I actually want to do something else if it's a multiline selection, so I do want to be able to get the final selection as well.

Answer 1

The event is global and shared between all extensions. For that reason a single extension cannot configure it. To handle the 'event avalanche' debouncing should be used. Instead of doing the work inside the event handler, schedule it to be done soon and cancel a potentially scheduled operation. Like so

let handle;
function doWorkNow() {
  // parse what is selected
}
onDidChangeTextEditorSelection(() => {
  clearTimeout(handle);
  handle = setTimeout(() => doWorkNow(), 10);
});