js写法

Question

this.check = function(shape, x, y, d){
            var r1=0,r2='N';
            for(var i=0;i<8;i+=2){
                if(shape[i]- -x < 0 && shape[i]- -x <r1)
                    {r1 = shape[i]- -x;}
                else if(shape[i]- -x>=this.width && shape[i]- -x>r1)
                    {r1 = shape[i]- -x;}
                if(shape[i+1]- -y>=this.height || this[shape[i]- -x- -(shape[i+1]- -y)*this.width])
                    {r2='D'}}
            if(d=='h'&&r2=='N')return r1>0?r1-this.width- -1:r1;
            else return r2;}
函数中的“shape[i]- -x”怎么理解？？跪求！

Answer 1

。。哇靠 我知道了，shape[i]- -x 就是 shape[i]+x