Fastmail Unsubscribe Button GreaseMonkey

philipbjorge-fastmail-unsubscribe.js

// ==UserScript==
// @name        Fastmail Unsubscribe
// @namespace   philipbjorge-fastmail-unsubscribe
// @include     https://*.fastmail.com/*
// @include     https://fastmail.com/*
// @require  http://ajax.googleapis.com/ajax/libs/jquery/1.7.2/jquery.min.js
// @require     https://gist.github.com/raw/2625891/waitForKeyElements.js
// @version     1
// @grant       GM_addStyle
// ==/UserScript==

// Makes contains case insensitive
jQuery.expr[':'].Contains = function(a, i, m) {
 return jQuery(a).text().toUpperCase()
     .indexOf(m[3].toUpperCase()) >= 0;
};

function unsubscribeInAnchor(node) {
  return jQuery(node).find("a:Contains('unsubscribe')");
};

function unsubscribeInHref(node) {
  return jQuery(node).find('a[href*="unsubscribe"]');
};

function linkNearUnsubscribeText(node) {
  return jQuery(node).find("a").parent(":Contains('unsubscribe')").filter(function(){
   return jQuery(this).find('a').length == 1;
  }).find("a");
};

waitForKeyElements (".v-Message-body", function(node) {
  jQuery("#fm-unsubscribe").remove();
  
  var unsubLink = null;
  var strategies = [unsubscribeInAnchor, unsubscribeInHref, linkNearUnsubscribeText];
  for(var i = 0; !unsubLink && i < strategies.length; i++) {
    var strategy = strategies[i];
    var result = strategy(node);
    unsubLink = (result.length == 0) ? null : result.eq(0).attr('href');
  }
  
  if (unsubLink) {
    jQuery(".v-Toolbar-section.v-Toolbar-section--right").append(
      jQuery("<button id='fm-unsubscribe' class='v-Button' style='filter: hue-rotate(100deg)'>" +
        "<span class='label'>Unsubscribe</span>" +
        "</button>")
    );
    
    jQuery("#fm-unsubscribe").click(function() {
      window.open(unsubLink);
    });
  }
});