IP地址如何转化，有人知道吗？

numberToIP(num: number): string { 
 let ip = '' 
 if (num < 0){ 
  return ip  
 } 
 let ip3 = (num << 0) >>> 24 
 let ip2 = (num << 8) >>> 24 
 let ip1 = (num << 16) >>> 24 
 let ip0 = (num << 24) >>> 24 
 ip = ip3.toString() + '.' + ip2.toString() + '.' + ip1.toString() + '.' + ip0.toString() 
 return ip  
}