SwapBranches(GitHub compare).js -- Bookmarklet for toggling/reversing order of [base: targetBranch] <-- [compare: sourceBranch]

SwapBranches(GitHub compare).js

// SwapBranches(GitHub compare).js -- Bookmarklet for toggling/reversing order of [base: targetBranch] <-- [compare: sourceBranch]

// 287 char: javascript:void function(){const a=a=>{const b=a?.href??a??"",c=/(\/compare\/)([^.\/]+)\.\.\.([^.\/]+)/;return c.test(b)?b.replace(c,(a,b,c,d)=>`${b}${d}...${c}`):b},b=(b=location)=>{const c=b?.href??b??"",d=a(c);return c!=d&&((b?.href?b:{}).href=d)};console.clear(),console.log(b())}();


const getSwappedGitHubBranches = (url) => {
  const href = url?.href ?? url ?? "";
  const pattern = /(\/compare\/)([^.\/]+)\.\.\.([^.\/]+)/;
  const replacer = (_, prefix, branch1, branch2) => `${prefix}${branch2}...${branch1}`

  if (!pattern.test(href)) {
    return href;
  } else {
    return href.replace(pattern, replacer);
  };
}

const reloadWithSwappedGitHubBranches = (loc = location) => {
  const href = loc?.href ?? loc ?? "";
  const swappedGitHubBranches = getSwappedGitHubBranches(href);

  if (href != swappedGitHubBranches) {
    return (loc?.href ? loc : {} ).href = swappedGitHubBranches;
  } else {
    return false;
  };
};

const with_swap_tests = () => {

  const swap1 = "https://github.com/MyOrg/MyRepo/compare/master...Name_Change";
  const swap2 = "https://github.com/MyOrg/MyRepo/compare/Name_Change...master";
  const swap3 = "https://github.com/MyOrg/MyRepo/main";

  console.log( {
    swap1: getSwappedGitHubBranches(swap1),
    swap2: getSwappedGitHubBranches(swap2),
    swap3: getSwappedGitHubBranches(swap3),
    href: getSwappedGitHubBranches(location.href),
    location: getSwappedGitHubBranches(location),
  } );

  console.log( {
    didSwap_1_is_now_2: getSwappedGitHubBranches(swap1) == swap2, // true
    didSwap_2_is_now_1: getSwappedGitHubBranches(swap2) == swap1, // true
    didSwap_3_is_now_not_3: getSwappedGitHubBranches(swap3) != swap3, // false
    reloadSwap1: reloadWithSwappedGitHubBranches(swap1), // https://github.com/MyOrg/MyRepo/compare/Name_Change...master (AKA swap2)
    reloadSwap2: reloadWithSwappedGitHubBranches(swap2), // https://github.com/MyOrg/MyRepo/compare/master...Name_Change (AKA swap1)
    reloadSwap3: reloadWithSwappedGitHubBranches(swap3), // false
  } );
};

console.clear();
// with_swap_tests();

console.log(reloadWithSwappedGitHubBranches());