fix(overmind): fix typing of transition and matches on statemachines

Author: christianalfoni

packages/node_modules/overmind/src/statemachine.ts

@@ -12,28 +12,28 @@ export type StatemachineTransitions<States extends TStates> = {
 
 export interface MachineMethods<States extends TStates> {
   reset: () => void
-  matches<T extends States["state"][]>(...states: T): this is Statemachine<States> & (States extends {
+  matches<T extends States["state"][]>(...states: T): this is Statemachine<States, States extends {
     state: T extends Array<infer S> ? S : never;
-} ? States : never);
-  transition<State extends States["state"], >(
+} ? States : never>;
+  transition<State extends States["state"]>(
     state: State,
-    entry?:  (current: Statemachine<States> & (States extends { state: State } ? States : never)) => void,
-    exit?: (current: Statemachine<States> & (States extends { state: State } ? States : never)) => void
+    entry?:  (current: Statemachine<States, States extends { state: State } ? States : never>) => void,
+    exit?: (current: Statemachine<States, States extends { state: State } ? States : never>) => void
   ): Promise<void>
   whenTransitioned: (state: States["state"]) => Promise<void>
 }
 
-export type Statemachine<States extends TStates> = States & MachineMethods<States>
+export type Statemachine<States extends TStates, State extends TStates = States> = State & MachineMethods<States>
 
 const CURRENT_EXIT = Symbol('CURRENT_EXIT')
 const INITIAL_STATE = Symbol('INITIAL_STATE')
 const TRANSITIONS = Symbol('TRANSITIONS')
 const PENDING_TRANSITIONS = Symbol('PENDING_TRANSITIONS')
 
-class StateMachine<States extends TStates>  {
-  state: States["state"]
+class StateMachine<States extends TStates, State extends TStates = States>  {
+  state: State["state"]
   private [CURRENT_EXIT]: (() => void) | undefined
-  private [INITIAL_STATE]: States["state"]
+  private [INITIAL_STATE]: State["state"]
   private [PENDING_TRANSITIONS]: { [key: string]: Function[] } = {}
   constructor(transitions: StatemachineTransitions<States>, definition: States) {
     this[INITIAL_STATE] = definition.state