What is wrong with my script?

EPICBRONY

var harvester = require('harvester');

for(var name in Game.creeps) {
    var creep = Game.creeps[name];
    harvester(creep);
}
if (creep.memory.role == 'harvester')
{
    if(creep.carry.energy < creep.carryCapacity) {
        var sources = creep.room.find(FIND_SOURCES);
        creep.moveTo(sources[0]);
        creep.harvest(sources[0]);
    }
    else {
        creep.moveTo(Game.spawns.Spawn1);
        creep.transferEnergy(Game.spawns.Spawn1)
    }
}
  var harvester = require('harvester');

for(var name in Game.creeps) {
    var creep = Game.creeps[name];

    if(creep.memory.role == 'harvester') {
        harvester(creep);
    }

    if(creep.memory.role == 'builder') {

        if(creep.carry.energy == 0) {
            creep.moveTo(Game.spawns.Spawn1);
            Game.spawns.Spawn1.transferEnergy(creep);
        }
        else {
            var targets = creep.room.find(FIND_CONSTRUCTION_SITES);
            if(targets.length) {
                creep.moveTo(targets[0]);
                creep.build(targets[0]);
            }
        }
    }
}
if(creep.memory.role == 'guard') {
    var targets = creep.room.find(FIND_HOSTILE_CREEPS);
    if(targets.length) {
        creep.moveTo(targets[0]);
        creep.attack(targets[0]);
    }
}

EPICBRONY

it runs smoothly in main with no others put when I spawn this
~~~
Game.spawns.Spawn1.createCreep( [WORK, CARRY, MOVE], 'Worker_Alpha', { role: 'harvester' } );
//then
Game.spawns.Spawn1.createCreep( [WORK, CARRY, MOVE], 'Builder_Alpha', { role: 'builder' } );
~~~
Worker_Alpha freezes
also I get an error saying harvester is not a function on line 5 and line 23

Maximumgame

You have var harvester = require('harvester'); in your code twice. Also at the top of your code you are telling every one of your creeps to harvest even if they don't have the harvester role. You should remove all of your code from the top to the second time you define harvester.

EPICBRONY

now with this code
~~~
var harvester = require('harvester');

if (creep.memory.role == 'harvester')
{
if(creep.carry.energy < creep.carryCapacity) {
var sources = creep.room.find(FIND_SOURCES);
creep.moveTo(sources[0]);
creep.harvest(sources[0]);
}
else {
creep.moveTo(Game.spawns.Spawn1);
creep.transferEnergy(Game.spawns.Spawn1)
}
}

for(var name in Game.creeps) {
var creep = Game.creeps[name];

if(creep.memory.role == 'harvester') {
    harvester(creep);
}

if(creep.memory.role == 'builder') {

    if(creep.carry.energy == 0) {
        creep.moveTo(Game.spawns.Spawn1);
        Game.spawns.Spawn1.transferEnergy(creep);
    }
    else {
        var targets = creep.room.find(FIND_CONSTRUCTION_SITES);
        if(targets.length) {
            creep.moveTo(targets[0]);
            creep.build(targets[0]);
        }
    }
}

}
if(creep.memory.role == 'guard') {
var targets = creep.room.find(FIND_HOSTILE_CREEPS);
if(targets.length) {
creep.moveTo(targets[0]);
creep.attack(targets[0]);
}
}
~~~
I get this error
[9:12:49 PM]TypeError: Cannot read property 'memory' of undefined
at main:3:10
at n:5:28406
at Object.c.runCode:5:34007