enum E {
  A,
  B
}

let e1: E = E.A
let e2: E = E.B

if (e1 === e2) {
  console.log("equal")
}

let e1: E = E.A
let e2: E = E.B


if (e1 as E === e2 as E) {
  console.log("equal")
}

let id = a => a

let e1: E = id(E.A)
let e2: E = id(E.B)

if (e1 === e2) {
  console.log('equal');
}

function id<T>(t: T): T { return t; }

if (e1.valueOf() === e2.valueOf()) {
  console.log("equal")
}

if (E[e1] === E[e2]) {
  console.log("equal")
}

if (product.ProductType &&
       (product.ProductType.toString() == ProductTypes[ProductTypes.Merchandises])) {
      // yes this item is of merchandises
  }