SOURCE

function* walk(str){
   let terminals = ['.','-']
   let part =''
   for(var i =0;i<str.length;i++){
       if(terminals.includes(str[i])){
           yield part
           part=''
       }else{
           part +=str[i]
       }
   } 
   if(part){
       yield part
   }
}

let a ="1.1.1.a"
let b = "1.1.1-apha.1"




const compare =(str1,str2)=>{
    if(str1.length>str2.length) [str1,str2] =[str2,str1] //保证循环长的字符串
    let interator1 = [...walk(str1)]
    let interator2 = [...walk(str2)]

    let res =''
    for(const index1 in interator1){
       for(const index2 in interator2){
          if(index1 != index2) continue
          if(interator1[index1] ==interator2[index2]) continue
          return +interator1[index1]>+interator2[index2]?str1:str2
       }
    }
    return str2
}

console.log(compare(a,b))