JoinMarket with already pruned node

[20kevin20]

I've been using JoinMarket on a full node for a while but I'm planning to switch to a smaller, less power-consuming device which doesn't have enough storage space to hold a full Bitcoin node on it. It's synced right now, but it's pruned. How can I set up JM to work with an already-existing ".dat" file rather than creating its own so that I don't have to resync the blockchain from zero?