// https://babeljs.io/docs/en/babel-plugin-proposal-function-bind

obj::func;
// is equivalent to:
func.bind(obj)::obj.func;
// is equivalent to:
obj.func.bind(obj);

obj::func(val);
// is equivalent to:
func
  .call(obj, val)

  ::obj.func(val);
// is equivalent to:
obj.func.call(obj, val);