function should return didginal root of number, this function return 'undefined' always, but variable contain corectly result ? Where is mistake?

function nuberRoot(a:number):number{
    let s:number = 0;
    while(a>0){
        s =a
        a = Math.floor(a /10)
    }
    if (s>=10){
        nuberRoot(s)
    }
    
    else{
        alert(s)//s=6
        return s//undefined
    }
    
}
alert(nuberRoot(942))//undefined

CodePudding user response：

You have missing return for if(s>=10)

function nuberRoot(a){
    let s = 0;
    while(a>0){
        s =a
        a = Math.floor(a /10)
    }
    if (s>=10){
        return nuberRoot(s)
    }
    
    else{
        alert(s)//s=6
        return s//undefined
    }
    
}
alert(nuberRoot(942))//undefined

CodePudding user response：

Logic is correct but return when s>10. Thanks.

if (s>=10){
      return  nuberRoot(s);
    }