code: func (jsre *JSRE) CompleteKeywords(line string) []string {
  	var results []string
  	jsre.Do(func(vm *otto.Otto) {
  		results = getCompletions(vm, line)
  	})
  	return results
  }
docs: // CompleteKeywords returns potential continuations for the given line. Since line is
  // evaluated, callers need to make sure that evaluating line does not have side effects.