interface InterfaceA {
  m1: string;
}
interface InterfaceB {
  m2: string;
}
type TypeAB = InterfaceA & InterfaceB;

interface X1 {
  m1: string;
}
interface X2 {
  m1?: string;
}
type Same = X1 & X2;
let same: Same = { m1: "This is required" };

// extending interfaces
interface InterfaceA {
  m1: string;
}

interface InterfaceB {
  m2: string;
}

// difference between type & interafces
type TPrimitive1 = string;
type TPrimitive2 = { m1: string };
// type can't be used to implement
class ExtendPrimitiv1 implements TPrimitive1 {
  // Does not compile
}
//

interface InterfaceMergeAB extends InterfaceA, InterfaceB {
  m3: string;
}