a very simple godot plugin that will keep track of what you type and emit signals based on whether it matches a sequence.
install the addons folder and paste it into your godot project, then, enable it in the project settings (Project -> Project Settings -> Plugins)
then, the StringSequence node will be available
you can assign a string to match with set_string(), and when you type it out properly, matched_sequence will be emitted
when you type a correct letter, correct_letter will be emitted (matched_sequence will be true if the correct letter is the last one)
when you type an incorrect letter, incorrect_letter will be emitted
and when there's any input, input will be emitted