This code will make Roomtodo load project with hash 'ckhUA37eeeb33'
iframeRoomtodo.contentWindow.postMessage(`{"action": "load_project", "hash": "ckhUA37eeeb33"}`, '*');
If the url of the current page was received from project sharing and contains hash of project, the project can be loaded in Roomtodo by this code
const parsedHash = new URLSearchParams(window.location.hash.substr(1));
if (parsedHash.has('project'))
{
iframeRoomtodo.contentWindow.postMessage(`{"action": "load_project", "hash": "${parsedHash.get('project')}"}`, '*');
}