Function to reveal the structure of an javascript web app

revealApp.js

function revealApp(app, tab) {
  tab = tab || "";
  Object.getOwnPropertyNames(app).forEach(function(key, idx, array) {
    var val = app[key],
      type = typeof(val),
      output = type !== "function" ? ( type !== "object" ? val : '' ) : 'function()';
    console.log(tab + key + ' -> ' + output);
    if ( type === 'object' && val != null ) {
      showall(val, tab + "    ");
    }
  });
}