Question

It’s my understanding now that I can declare an interface like this:

interface IParams {
    success: bool;
    pk: string;
}

and a function like this:

function x () : IParam {
   var params = {
      success: true,
      pk: "xx"
   };
   return params;
}

This works fine but is there a way that I could do this and have the
params variable only accept values of success and pk? What I want is some way that will stop me from doing the following:

function x () : IParam {
   var params = {
      successssssssssssss: true,
      pk: "xx"
   };
   return params;
}

Answer 1

Simply putting a type annotation on the var declaration should do what you want:

var params : IParams = {
  success: true,
  pk: "xx"
};