姓名脱敏

function encryptName(str,x=false) {
  if(str && str.length && str.length > 2){
    var y = '*'.repeat(str.length - 2)
    var last = x ? str.slice(-1) : '*'
    return str.slice(0,1).concat(y+last)
 }else{
   return str
 }
}

var x1 = encryptName('三个字')
var x11 = encryptName('三个字',true)
var x111 = encryptName('三')
var x2 = encryptName('三个dddd字',true)
var x3 = encryptName('二字')
console.log(x1,x11, x111,x2,x3)

"三**"
"三*字"
"三"
"三*****字"
"二字"