extract method type from class

type ReturnedActions<T> = {
    [P in keyof T]: T[P] extends (...a: any) => infer R ? {
        type: P,
        payload: R
    } : never
}[keyof T]

type AllActions = ReturnedActions<Actions>

Playground link

Edit If Actions only contains functions, you can also use the distributive nature of ReturnType to get the return type of all functions in Actions:

type AllActions = ReturnType<Actions[keyof Actions]>;

type ReturnedActions<T> = {
  // eslint-disable-next-line no-unused-vars
  [P in keyof T]: T[P] extends (...args: any) => infer R ? {
    type:P,
    payload:R
  }:never
}[keyof T]

class Test {
  constructor(){}

  hello():void{
    console.log('hello')
  }
  num():number{
    return 1
  }
}

type TestAction = ReturnType<Test[keyof Test]>
type Ret = ReturnedActions<Test>

class Drill {
  constructor() {}

  consoleHi(): string {
    return 'Hi';
  }
}

type DrillAction = ReturnType<Drill[keyof Drill]>;