Data types in Flow

sample-fp.js

// Definition
export type Primitive = { type: string; };

// 'Factory' 
export function Primitive(type:string) {
  return {
    type: string;
  }
}

// Flow throws error since `Primitive` is a duplicated declaration.
// Which is the 'nice way' in order to declare factories & data type definitions?

// I'd like to avoid something like `function primitive()` since the cap specifies 
// it's a Data type factory and not just a common function, but I don't know if this is correct.