javascript replace big list

var obj = {
  'firstname': 'John',
  'lastname': 'Doe'
}

var text = "My firstname is {firstname} and my lastname is {lastname}"

alert(mutliStringReplace(obj,text))

function mutliStringReplace(object, string) {
      var val = string
      var entries = Object.entries(object);
      entries.forEach((para)=> {
          var find = '{' + para[0] + '}'
          var regExp = new RegExp(find,'g')
       val = val.replace(regExp, para[1])
    })
  return val;
}