bitcoin-node-stub.js

type BitcoinNodeType = {|
    mine : () => Promise<void>,
    send : (receiver : string, amount : number, fee : number) => Promise<void>
|};

export function BitcoinNode() : BitcoinNodeType 

    const mine = async () : Promise<void> => {

    };

    const send = async (receiver : string, amount : number, fee : number) : Promise<void> => {

    };

    return {
        mine,
        send
    };
}