Custom console object to allow for objects to be printed correctly in the console from within LWC by leveraging iframes.

lwc-console-override.js

/**
 * Custom console object to allow for objects to be printed correctly in the
 * console by leveraging iframes.
 * @type {Console}
 */
const CONSOLE = ((realConsole) => {
  let iframe;
  try {
    iframe = document.createElement('iframe');
    iframe.style.display = 'none';
    document.body.appendChild(iframe);
    
    const interval = setInterval(
      () => {
        if (iframe.contentDocument.readyState !== 'loading') {
          clearInterval(interval);
          iframe.contentWindow.addEventListener('message', ({data: {consoleFuncName, consoleFuncNameArgs}}) => {
            if (consoleFuncName && consoleFuncNameArgs) {
              console[consoleFuncName](...consoleFuncNameArgs);
            }
          });
        }
      },
      50
    );
  } catch (err) {}

  // Returns the actual console object.
  return Object.keys(realConsole).reduce(
    (CONSOLE, consoleFuncName) => {
      CONSOLE[consoleFuncName] = function() {
        try {
          iframe.contentWindow.postMessage({consoleFuncName, consoleFuncNameArgs: [...arguments]});
        }
        catch (err) {
          realConsole[consoleFuncName](...arguments);
        }
      };
      return CONSOLE;
    },
    {}
  );
})(console);