The documentation for child_process.spawn() (http://www.nodejs.org/api/child_process.html#child_process_child_process_spawn_command_args_options) suggests that both the args and options arguments are optional. However spawn('ls', { cwd: process.cwd() }) errors with

child_process.js:699
  args = args ? args.slice(0) : [];
                     ^
TypeError: Object #<Object> has no method 'slice'

It can be worked around with spawn('ls', [], { cwd: process.cwd() }).

This is on 0.10.16.