disriminate-union-utils.ts

export type DiscriminateUnion<
  T,
  K extends keyof T,
  V extends T[K]
> = T extends Record<K, V> ? T : never;

export type MapDiscriminatedUnion<
  T extends Record<K, string>,
  K extends keyof T
> = {
  [V in T[K]]: DiscriminateUnion<T, K, V>;
};

type T1 = {
  name: 'T1';
  t1foo: true;
  t1bar: 1;
};

type T2 = {
  name: 'T2';
  t2foo: [1, 2];
  t2bar: 'hello world';
};

type T3 = {
  name: 'T3';
  t3foo: number[];
  t3bar: 'hello world' | false;
};

type Plugins = T1 | T2 | T3;

export type test = DiscriminateUnion<Plugins, 'name', 'T2'>;

export type testmap = MapDiscriminatedUnion<Plugins, 'name'>;