Prettify

A TypeScript type alias called Prettify. It takes a type as its argument and returns a new type that has the same properties as the original type, but the properties are not intersected. This means that the new type is easier to read and understand.

type Prettify<T> = {
  [K in keyof T]: T[K];
} & {};

For deeply nested types:

type Prettify<T> = {
  [K in keyof T]: T[K] extends object ? Prettify<T[K]> : T[K];
} & {};

Use case

Suppose we have a type that has many intersections:

export type SimpleShape = {
  color: string;
} & {
  size: number;
} & {
  shape: 'circle' | 'square';
};

When we hover over the type SimpleShape with many intersections, it can be difficult to see the resolved type. It would be helpful if there was a way to prettify the display of these types.

With Prettify we can exactly do so, using:

type Shape = Prettify<SimpleShape>;
//   ^? type Shape = {
//        color: string;
//        size: number;
//        shape: "circle" | "square";
//      }