It's no bother at all! I'm happy to help. You can use the prereqs to do this. You can make up any arbitrary string as a prerequisite, for instance 'door', and place it on the line you wish to hide, like this:
{ option: 'How do I UNLOCK this door?', line: 'You have to use a key, of course!', prereqs: ['door'] }
Now the option won't show up until some code runs that pushes that prerequisite onto the character's chatLog. You could do this, for instance, in the onLook callback for the door like this:
{
name: 'door',
desc: 'It\'s locked.',
onLook: () => {
const npc = getCharacter('gregory');
npc.chatLog.push('door');
}
}
Now you've met the prerequisite for discussing the door with Gregory (or whatever your NPC's name is). The next time you talk to him, the topic will show up.
This technique is used in the "ur dead" demo. After you learn from the character Fran about how names work in the underworld, it unlocks the ability to ask the other characters you've met what their names are.
If you have more questions, don't hesitate to ask. Like I said, happy to help!