Show HN: All visitors pointers on a webpage (How-to) | Hacker News Reader

Show HN: All visitors pointers on a webpage (How-to)

hexagon.56k.guru

8 pointsHexagon56k9 comments

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https://dimden.dev/

Dimden shows all mouse pointers on the web page, the page in general is absolute mint.

Wonderful, reminds me of the good old days!

I'm curious how well will it work with 5 thousand pointers...

Would work quite well i think, at last if deployed to deno deploy

And kill browsers...

  ws.onmessage = function(event) {
  
  Object.keys(cursors).forEach((id) => {
          if (!positions.find((pos) => pos.id === id)) {
            document.body.removeChild(cursors[id]);
            delete cursors[id];
          }
        });

If I'm not mistaken, this has O(n^2) complexity and is executed on EACH position update. Unless it's autooptimized to not be a linear search on positions?

It was just a quickie for fun, but maybe I should look into that

Yeah, I’d maybe make a set of just the position IDs, and do a negated .has() of that set to check if the cursor was removed.

    ws.onmessage = function(event) {
      const positionIds = new Set(positions.map(pos => pos.id));

      Object.keys(cursors).forEach((id) => {
        if (!positionIds.has(id)) {
            document.body.removeChild(cursors[id]);
          delete cursors[id];
        }
      });
    };

Untested but that’s probably pretty close for phone typing

Any code written on a phone is impressive ^^ Will try it out

Implemented and working, should probably move this whole thing outside ws.onmessage too, could be run every fifth second or so.

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