upgrader.js

module.exports = {
    run: function(creep) {
        if(creep.store.getFreeCapacity() > 0 && creep.memory[delivering]) {
            creep.memory[delivering] = false;
        }
        else {
            if(creep.store.getFreeCapacity() = 0 && !creep.memory[delivering]) {
                creep.memory[delivering] = true;
            }
        }

        if(creep.memory[delivering]) {
            if(creep.transfer(creep.room.controller) == ERR_NOT_IN_RANGE) {
                creep.moveTo(creep.room.controller);
            }
        } else {
            var sources = creep.room.find(FIND_SOURCES);
            if(creep.harvest(sources[0]) == ERR_NOT_IN_RANGE) {
                creep.moveTo(sources[0]);
            }
        }
    },

    spawnInfo: {
        count: 1,
        label: 'Upgrader',
        body: [WORK, CARRY, MOVE, MOVE],
        startMemory: {delivering: false}
    }
}