@orlet Thanks.

Thanks for the help. That is what was going wrong.

Working on a function to build a creep based on a given main body then add repeat body parts until energy is used up or repeated x number of times. When I use the bodyMain: [WORK, CARRY, MOVE] passed to the function it work great. When I create a new array and push() the bodyMain to the array, i get an error ERR_INVALID_ARGS -10 Body is not properly described or name was not provided. Not sure what I am doing wrong with my code below.

var roleProperty = {
  harvester:{ maxNum: 2,
              bodyMain: [WORK, CARRY, MOVE],
              bodyRepeat: [MOVE, CARRY],
              repeatMax: 2,},
  };

StructureSpawn.prototype.checkCreepNumbers =
function () {

        this.createDefaultCreep('harvester', roleProperty['harvester'].bodyMain, roleProperty['harvester'].bodyRepeat);
    
}
              // spawns a creep based on passed parameters
              // roleName -> role assigned to Memory
              // mainParts -> base body parts to used
              // repeatParts -> what parts to repeat
              //
              StructureSpawn.prototype.createDefaultCreep =
              function (roleName, mainParts , repeatParts ) {
                var creepName = roleName  + Game.time;
                var bodyBuild = [];
                bodyBuild.push(mainParts);

                var creepMaker = 
                          this.createCreep(mainParts, creepName, { role: roleName, working: false });  //WORKS
                var creepMaker = 
                          this.createCreep(bodyBuild, creepName, { role: roleName, working: false }); // Return -10
          
                return creepMaker;
              };
'''