screeps/role.miner.js

var roleMiner = {

    /** @param {Creep} creep **/
    run: function(creep,mysource) {
        var sources = creep.room.find(FIND_SOURCES);
        if(creep.harvest(sources[0]) == ERR_NOT_IN_RANGE) {
            creep.moveTo(sources[0]);
        } 
    },
    spawn: function(){
        var myrole='miner';
        var nummyrole=1;
        var myroles = _.filter(Game.creeps, (creep) => creep.memory.role == myrole);
        if(myroles.length < nummyrole) { 
            
            console.log('Miners: ' + myroles.length + ' Needed: ' + nummyrole);
            var newName = Game.spawns['Spawn1'].createCreep([WORK,WORK,WORK,WORK,WORK,MOVE], undefined, {role: myrole});
            console.log('Spawning new ' + myrole + ': ' + newName);
        }
    }

};

module.exports = roleMiner;