Raw Source
sjehuda / Replace Sign Up by Sign In 

// ==UserScript== 
// @name        Replace Sign Up by Sign In
// @author      Schimon Jehudah, Adv.
// @copyright   2022, Schimon Jehudah (http://schimon.i2p)
// @license     AGPL-3.0-only; https://www.gnu.org/licenses/agpl-3.0.en.html
// @namespace   org.openuserjs.sjehuda.replacesignup
// @description Replace button Sign Up by button Sign In
// @include     https://github.com/* 
// @version     1.0.0 
// @grant       none
// ==/UserScript==

logo = document.querySelector('a > svg');
logo.remove()

try{
  menu = document.querySelector('div.flex-1.flex-order-2.text-right > button');
  menu.remove()
}
catch(error){
  // User is logged in. Nothing to do.
  //console.info("Menu was not removed")
}

snup = document.querySelector('div.d-flex.flex-justify-between.flex-items-center.width-full.width-lg-auto > div:nth-child(2) > a');
snin = document.querySelector('div > div.position-relative.mr-lg-3.d-lg-inline-block > a');
try{
  snup.innerText = "Login";
  snup.href = snin.href;
}
catch(error){
  // User is logged in. Nothing to do.
  //console.info("Link was not found")
}

// HELP NEEDED
// The original order was Sign In button, Search bar, and Sign Up button.
// Due to the website complexity, I didn't do so and the search bar was too wide.
// You're welcome to take over this program.

// relevant element

//sin = document.querySelector('div.position-relative.mr-lg-3.d-lg-inline-block > a');
//sin.className = 'd-inline-block d-lg-none flex-order-1 f5 no-underline border color-border-default rounded-2 px-2 py-1 color-fg-inherit'
//sin = sin.href;

//let sin_new = document.createElement("a");
//sin_new.href = sin;
//sin_new.innerHTML = "Sign in";
//sin_new.className = "HeaderMenu-link no-underline px-0 px-lg-2 py-3 py-lg-2 d-block d-lg-inline-block";

//let sin_div = document.createElement("div");
//sin_div.appendChild(sin_new);
//sin_div.className = "flex-1";

//sin_mnu = document.querySelector('nav > ul > li:nth-child(4) > a');
//sin_mnu.replaceWith(sin_new);

//sup = document.querySelector('div.d-flex.flex-justify-between.flex-items-center.width-full.width-lg-auto > div:nth-child(2) > a');
//sup.innerText = sin.innerText;
//sup.href = sin.href;

//let sup_new = document.createElement("a");
//sup_new.href = sup;
//sup_new.innerHTML = "Sign up";
//sup_new.className = "HeaderMenu-link no-underline px-0 px-lg-2 py-3 py-lg-2 d-block d-lg-inline-block";

//let sup_div = document.createElement("div");
//sup_div.appendChild(sup_new);
//sup_div.className = "flex-1"

//sup_mnu = document.querySelector('nav > ul > li:nth-child(2) > button');
//sup_mnu.replaceWith(sup_new);

// locate search bar
//sea = document.querySelector('div.d-lg-flex.min-width-0.mb-2.mb-lg-0 > div');


//let new_ele = document.createElement("header");
//new_ele.appendChild(sup_div);
//new_ele.appendChild(sin_div);
//new_ele.style.left = 0;
//new_ele.style.right = 0;
//new_ele.style.top = 0;

//ele = document.querySelector('header');
//ele.remove();
//ele.replaceWith(new_ele);

//head = document.querySelector('body > div.logged-out.env-production.page-responsive > div.position-relative.js-header-wrapper > header');
//head.appendChild(sea);
//head.appendChild(sin_new);
//head.appendChild(sup_new);
//head.appendChild(sin_div);
//head.appendChild(sup_div);



// irrelevant elements

// locate logo
//logo = document.querySelector('div.d-flex.flex-justify-between.flex-items-center.width-full.width-lg-auto > a');
//logo.replaceWith(snup);

// locate navigation bar
//nbar = document.querySelector('div.HeaderMenu--logged-out.p-responsive.height-fit.position-lg-relative.d-lg-flex.flex-column.flex-auto.pt-7.pb-4.top-0 > div > nav');
//nbar.remove();

// locate menu
//mbar = document.querySelector('div.flex-1.flex-order-2.text-right > button');
//mbar.remove();
//mbar.replaceWith(sin_div);

// replace menu with link
//mbar.replaceWith(link);

// locate search placeholder
//rbar = document.querySelector('div > div > div.d-lg-flex.min-width-0.mb-2.mb-lg-0');
//rbar.append(snup);

// locate navigation bar placeholder
//nbar = document.querySelector('div.HeaderMenu--logged-out.p-responsive.height-fit.position-lg-relative.d-lg-flex.flex-column.flex-auto.pt-7.pb-4.top-0');
//nbar.append(sbar);
//nbar.replaceWith(sbar);

// locate right placeholder
//sin_bar = document.querySelector('div.flex-1.flex-order-2.text-right');
//sin_bar.replaceWith(sin_div);