methods: {
    setCameraPostion: (()=>{
        let _eye = new Vector3();
        let eyeDirection = new Vector3();
        let target = new Vector3();
        let distance, newDistance;
        return function setCameraPostion(args) {
            _eye.copy(args.pos).sub(target);
            eyeDirection.copy(_eye).normalize();
            distance = _eye.length();
            newDistance = ...(有点长，略过);
            eyeDirection.setLength(newDistance).add(target);
            return eyeDirection;
        }
    })(),
}

以上写法是可以执行的，我想问得是这种写法是否可取？需不需要优化？
个人感觉这种辅助变量写在data里很别扭...强迫症了快
但缺点是无法使用this——不知道怎么用
谢谢