isResolvable() {
        if (this.alwaysResolve) return true;
        for (let i = 0; i < this.nodeList.length; i++) { if (this.nodeList[i].type === 0 && this.nodeList[i].value === undefined) return false; }
        return true;
    }
Method to check if object can be resolved
OVERRIDE if necessary
@return {boolean}