ActorID Pseudo code, Help Please

// There is a bug where I attempt to get an ActorID from an animation that was just remove and is assigned with that ID and then another new animation is added and it's assigned that same ID. I'm not sure if it's a timing thing or if I've made bad code
//For more information please look at my tweet: https://twitter.com/WinderpTV/status/1345439896299855872?s=20

var actorsArr = [
    {actorName: "Putt-Putt", actorID:1},
    {actorName: "SomeRadomAnimation1", actorID:2},
    {actorName: "SomeRadomAnimation2", actorID:3}
];
function getNextActorID(){
    var _loc1 = 0;//index
    var _loc2 = 1;//ActorID
    while (true) {
        if(ACTOR ID FROM actorsArr IS IN USE){
            continue;
        }
        //OTHERWISE GIVE ME USABLE ACTOR ID THAT'S NOT FOUND IN actorsArr
        return _loc2;
    }
    //NOTHING TO GIVE
    return -1;
}

function addActor(startingCostume, isIdle = false, isPlayer = false, roomOverride = undefined, startFrame = 0, target = undefined, color = ""){
    //GET AVAIBLE ACTOR ID
    //ADD ANIMATION SPRITE BASED ON ACTOR ID

    //What I done to achieve this...
    var _actorID = this.getNextActorID();
    var _index = (this.actors.push(new com.wtv.Test(this, _actorID, isPlayer))) - 1;

    return ({actor:this.actors[_index], actorID:_actorID});
}// end of the function

function removeActor(actorID, doSplice = true, removeTarget = true) {
    //REMOVE ACTOR FROM actorsArr BASED ON actorID GIVEN

    //What I done to achieve this...
    var index = this.getActorIndexByID(actorID, 'removeActor2');
    var actor = this.actors[index];
    this.actors.splice(index, 1);
}// end of the function