React with Flow

Bad // ERROR: Must be a ReactElement const element = 'just a string'; // type is interred as string ReactDOM.render(element, mountNode); Generics aka Parametric Types Consider this type hierarchy class Animal { name: string; constructor(name: string) { this.name = name; } } class Dog extends Animal { // just to make this different from cat goodBoyFactor: number; } class Cat extends Animal { purrFa