console.api()

example.js

function params(fn) {
  var str = fn.toString();
  var sig = str.match(/\(([^)]*)\)/)[1];
  if (!sig) return [];
  return sig.split(', ');
}

console.api = function(obj){
  console.log();
  var proto = Object.getPrototypeOf(obj);
  console.log('  %s:', obj.constructor.name);
  for (var key in proto) {
    if (proto.hasOwnProperty(key)) {
      console.log('   - %s(%s)', key, params(proto[key]).join(', '));
    }
  }
  console.log();
};

out

  Item:
   - isNew()
   - toJSON()
   - file(file)
   - link(url)
   - remove(fn)
   - set(prop, val, fn)
   - load(fn)
   - create(fn)
   - thumb(path, fn)
   - postFile(fn)
   - postURL(fn)
   - save(fn)

This is neat. Will be using this for my constructors so that I can reformat and/or remove prototype functions.