movement?

ReferenceError: creep is not defined
at main:2:4
at n:5:28406
at Object.c.runCode:5:34007
that is the error, what is up?
and here is the script in main that I was using

// memory roles
if(creep.memory.role == 'harvester') {
  harvester(creep);
}
if(creep.memory.role == 'builder') {
  builder(creep);
}
if(creep.memory.role == 'guard') {
  guard(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);
    }
}

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]);
    }
  }

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

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

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]);
    }
}