Question

Is there a better way of executing the string “getData” without eval or eval a good option in this case since what is being evaluated is not user generated?

object.myMainObject(Marcus)

object = {
    Data = {
        Marcus : function(){
            alert('marcus function')
        },
        James : function(){
            alert('james function')
        }
    }

    myMainObject : function(string){
        getData = "object.Data." + string + "()"

        eval(getData)
    }
}

Answer 1

eval is completely unnecessary for this case, just use the bracket notation to access the dynamically named property:

var object = {
    Data : {
        Marcus : function(){
            alert('marcus function');
        },
        James : function(){
            alert('james function');
        }
    }

    myMainObject : function(string){
        var getData = object.Data[string]();
    }
};

object.myMainObject("Marcus"); // 'marcus function'

Notes:

• There were some syntax errors in the way you were defining object (you were using =, instead of : ).
• You weren’t using the var statement to declare object nor getData, please, when declaring variables, use the var statement, otherwise, they will end up as properties of the global object.

• As a safety measure, you could check if the member that’s being accessed is actually a function before calling it, e.g.:

  //...
  var getData;
  if (typeof object.Data[string] == 'function') {
     getData = object.Data[string]();
  }
  //...