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I browse Reddit frequently throughout the day, and I hate seeing posts that I have already read on my feed.

So, I wrote a little bookmarklet to hide them.

javascript: (() => {document.querySelectorAll('.noCtrlF').forEach(link => link.click())})();

You need 2 things to make this work:

  1. You need to use the old.reddit.com layout
  2. You need to use a Chrome extension called Reddit Enhancement Suite which adds extra features to Reddit but only supports the old layout

RES has this feature where you can show a hide link button below each Reddit post. What the bookmarklet does is just click that button on all the visible posts, essentially hiding every post on my screen.