script.user.js

// ==UserScript==
// @name         Get CRX
// @description  Download CRX of extension from Chrome Web Store
// @match        https://chrome.google.com/webstore/*
// @grant        none
// @version      2.0
// ==/UserScript==


var getExtensionIdFromLocation = function ( location ) {

  var pathnameParts = location.pathname.split( '/' );

  if ( pathnameParts.length !== 5 ) return;

  var extensionId = pathnameParts[ 4 ];

  return extensionId;

};


var CHROME_VERSION = /Chrome\/(\d+\.\d+)/.exec( navigator.userAgent )[ 1 ];

var DOWNLOAD_URL_TEMPLATE = 'https://clients2.google.com/service/update2/crx?response=redirect&prodversion=[CHROME_VERSION]&x=id%3D[EXTENSION_ID]%26installsource%3Dondemand%26uc';

var BUTTON_HTML_TEMPLATE = '<a role="button" class="dd-Va g-c g-c-wb" aria-label="Download CRX" tabindex="0" style="user-select: none;" href="[URL]"><div class="g-c-Hf"><div class="g-c-x">Download CRX</div></div></a>';

var getButtonHtmlForExtension = function ( options ) {

  var extensionId = options.extensionId;

  var className = options.className;


  var url = DOWNLOAD_URL_TEMPLATE;

  url = url.replace( '[CHROME_VERSION]', CHROME_VERSION );

  url = url.replace( '[EXTENSION_ID]', extensionId );


  var buttonHtml = BUTTON_HTML_TEMPLATE;

  buttonHtml = buttonHtml.replace( '[URL]', url );

  buttonHtml = buttonHtml.replace( '[CLASS_NAME]', className );


  return buttonHtml;

};


var MARK_CONTAINER_ATTRIBUTE = 'data-crx';

var markContainer = function ( container ) {

  if ( container.getAttribute( MARK_CONTAINER_ATTRIBUTE ) ) return false;

  container.setAttribute( MARK_CONTAINER_ATTRIBUTE, true );

  return true;

};


var INDIVIDUAL_LINK_CONTAINER_SELECTOR = '.h-e-f-Ra-c.e-f-oh-Md-zb-k';

var INDIVIDUAL_LINK_CLASS_NAME = '';

var handleIndividualLink = function () {

  var extensionId = getExtensionIdFromLocation( window.location );

  if ( ! extensionId ) return;


  var container = document.querySelector( INDIVIDUAL_LINK_CONTAINER_SELECTOR );

  if ( ! container ) return;


  if ( ! markContainer( container ) ) return;


  container.innerHTML = getButtonHtmlForExtension( {

    extensionId: extensionId,

    className: INDIVIDUAL_LINK_CLASS_NAME,

  } );

};


var LIST_LIST_CONTAINER_SELECTOR = '.h-d-Ra-c.d-Ra-c';

var LIST_LINK_CLASS_NAME = '';

var handleListLinks = function () {

  var containers = document.querySelectorAll( LIST_LIST_CONTAINER_SELECTOR );

  containers.forEach( function ( container ) {

    if ( ! markContainer( container ) ) return;


    var link = container.parentNode.parentNode.parentNode.parentNode;

    if ( link.tagName !== 'A' ) return;


    var extensionId = getExtensionIdFromLocation( link );

    if ( ! extensionId ) return;


    container.innerHTML = getButtonHtmlForExtension( {

      extensionId: extensionId,

      className: LIST_LINK_CLASS_NAME,

    } );

  } );

};


setInterval( function () {

  handleIndividualLink();

  handleListLinks();

}, 500 );