Resizable Diff Sidebar (GitHub PR Files)

Make GitHub PR diff sidebar resizable with a visible drag handle

You will need to install an extension such as Tampermonkey, Greasemonkey or Violentmonkey to install this script.

You will need to install an extension such as Tampermonkey or Violentmonkey to install this script.

You will need to install an extension such as Tampermonkey or Violentmonkey to install this script.

You will need to install an extension such as Tampermonkey or Userscripts to install this script.

You will need to install an extension such as Tampermonkey to install this script.

You will need to install a user script manager extension to install this script.

(I already have a user script manager, let me install it!)

You will need to install an extension such as Stylus to install this style.

You will need to install an extension such as Stylus to install this style.

You will need to install an extension such as Stylus to install this style.

You will need to install a user style manager extension to install this style.

You will need to install a user style manager extension to install this style.

You will need to install a user style manager extension to install this style.

(I already have a user style manager, let me install it!)

// ==UserScript==
// @name         Resizable Diff Sidebar (GitHub PR Files)
// @namespace    http://tampermonkey.net/
// @version      1.3
// @icon         https://www.google.com/s2/favicons?sz=64&domain=github.com
// @description  Make GitHub PR diff sidebar resizable with a visible drag handle
// @author       Louis Yvelin
// @match        https://github.com/*/*/pull/*/files*
// @grant        none
// @license MIT
// ==/UserScript==

(function() {
    'use strict';

    const parent = document.querySelector("#diff-layout-component")
    const sidebar = document.querySelector("#diff-layout-component > div.Layout-sidebar.overflow-y-auto.hx_Layout--sidebar.diff-sidebar.position-sticky div")

    if (!parent || !sidebar) return

    const handle = document.createElement("div")
    handle.style.width = "5px"
    handle.style.cursor = "col-resize"
    handle.style.position = "absolute"
    handle.style.top = "0"
    handle.style.bottom = "0"
    handle.style.right = "0"
    handle.style.zIndex = "9999"
    handle.style.background = "rgba(0, 123, 255, 0)"
    handle.style.transition = "background 0.2s ease"

    sidebar.style.position = "relative"
    sidebar.appendChild(handle)

    sidebar.addEventListener("mouseenter", () => {
        if (!isDragging) handle.style.background = "rgba(0, 123, 255, 0.5)"
    })
    sidebar.addEventListener("mouseleave", () => {
        if (!isDragging) handle.style.background = "rgba(0, 123, 255, 0)"
    })

    let isDragging = false

    handle.addEventListener("mousedown", e => {
        e.preventDefault()
        isDragging = true
        document.body.style.userSelect = "none"
        handle.style.background = "rgba(0, 123, 255, 0.9)"
    })

    document.addEventListener("mousemove", e => {
        if (!isDragging) return
        const rect = parent.getBoundingClientRect()
        const newWidth = e.clientX - rect.left
        parent.style.setProperty("--Layout-sidebar-width", `${newWidth}px`)
    })

    document.addEventListener("mouseup", () => {
        if (isDragging) {
            isDragging = false
            document.body.style.userSelect = ""
            handle.style.background = "rgba(0, 123, 255, 0.5)"
        }
    })
})()