Optional Arguments

Most methods provided through the API support a number of different optional arguments that that augment the behavior and/or return results of the process being called. Most optional arguments are provided through predefined variables that are grouped together in a single object.

JavaScript does not natively support named keyword arguments like Python; so all named optional arguments must be provided using the single object format.

Predefined Variable Syntax

All predefined optional argument variable names must be provided as strings; while this isn't necessary when writing screeps code in JavaScript, failing to provide arguments as strings will either cause build.py to fail, or, Screeps itself won't recognize the variable name. This rule holds true for every API call except for arguments that allow for a custom CostMatrix; you can read more about this in the PathFinder - CostMatrix section.

Examples

Modifying .moveTo() behavior:

creep.moveTo(creep.room.controller, {'maxRooms': 1, 'ignoreCreeps': True})

Spawning a creep with predefined memory:

name = "{}{}".format('harvester', Game.time)
spawn.spawnCreep([WORK, CARRY, MOVE], name, {'memory': {'role': 'harvester'}})