1 files changed, 23 insertions, 0 deletions
diff --git a/content.js b/content.js
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+// ... / NixOS / nixpkgs / pull / <number> / ...
+const number = new URL(window.location.href).pathname.split('/')[4]
+
+// There are (at the time of writing) two contexts in which the PR
+// number is visible:
+//
+//   1. in the header (following the PR title)
+//   2. sufficiently far down that the header is no longer visible (at
+//   which point the header shrinks and affixes itself to the top of the
+//   page)
+//
+// These are actually two distinct elements, the visibility of which
+// are dependent on your scroll position. They also have completely
+// different (and nondescript) CSS selectors, so instead of looking for
+// them directly, we locate the immediately preceding PR title elements
+// (which do have a common CSS selector), and grab their next sibling.
+for (let node of document.querySelectorAll('.js-issue-title')) {
+  node = node.nextElementSibling
+  const a = document.createElement('a')
+  a.setAttribute('href', `https://nixpk.gs/pr-tracker.html?pr=${number}`)
+  node.replaceWith(a)
+  a.appendChild(node)
+}