screeps/main.js

var roleHarvester = require('role.harvester');
var roleUpgrader = require('role.upgrader');
var roleBuilder = require('role.builder');

var creepsConfig = {
    harvester: {
        bodyParts: [WORK, CARRY, MOVE],
        minimumCreeps: 4,
        role: roleHarvester
    },
    builder: {
        bodyParts: [WORK, CARRY, MOVE],
        minimumCreeps: 2,
        role: roleBuilder
    },
    upgrader: {
        bodyParts: [WORK, CARRY, MOVE],
        minimumCreeps: 2,
        role: roleUpgrader
    }
}

module.exports.loop = function(){
    // Cleanup Creeps
    for (var name in Memory.creeps){
        if (!Game.creeps[name]){
            delete Memory.creeps[name];
            console.log("Clearning non-existing creep memory: ", name);
        }
    }
    // Refactor some similar behavior for all roles

    for (var roleName in creepsConfig){
        var creepsOfKind = _.filter(Game.creeps, (creep) => creep.memory.role == roleName);
        if (creepsOfKind.length < creepsConfig[roleName].minimumCreeps){
            var newName = Game.spawns.Spawn1.createCreep(creepsConfig[roleName].bodyParts, 
                                                         undefined, 
                                                         {role: roleName});
            console.log("Spawning new ", roleName, ": ", newName);
        }
    };

    // Run stuff for each creep
    for (var name in Game.creeps){
        var creep = Game.creeps[name];
        var role = creep.memory.role;
        creepsConfig[role].role.run(creep);
    }
}