119db8fb #1577 Thanks @davidkpiano! - Expressions can now be used in the stop() action creator:

// ...
actions: stop(context => context.someActor);

8c78e120 #1570 Thanks @davidkpiano! - The return type of spawn(machine) will now be Actor<State<TContext, TEvent>, TEvent>, which is a supertype of Interpreter<...>.

602687c2 #1566 Thanks @davidkpiano! - Exit actions will now be properly called when an invoked machine reaches its final state. See #1109 for more details.

6e44d02a #1553 Thanks @davidkpiano! - The state.children property now properly shows all spawned and invoked actors. See #795 for more details.

72b0880e #1504 Thanks @Andarist! - Added status property on the Interpreter - this can be used to differentiate not started, running and stopped interpreters. This property is best compared to values on the new InterpreterStatus export.

b1684ead #1402 Thanks @Andarist! - Improved TypeScript type-checking performance a little bit by using distributive conditional type within TransitionsConfigArray declarations instead of a mapped type. Kudos to @amcasey, some discussion around this can be found here

ad3026d4 #1407 Thanks @tomenden! - Fixed an issue with not being able to run XState in Web Workers due to assuming that window or global object is available in the executing environment, but none of those are actually available in the Web Workers context.

4e949ec8 #1401 Thanks @Andarist! - Fixed an issue with spawned actors being spawned multiple times when they got spawned in an initial state of a child machine that is invoked in the initial state of a parent machine.

const child = createMachine({
  initial: 'bar',
  context: {},
  states: {
    bar: {
      entry: assign({
        promise: () => {
          return spawn(() => Promise.resolve('answer'));
        }
      })
    }
  }
});
const parent = createMachine({

initial: 'foo',

states: {

foo: {

invoke: {

src: child,

onDone: 'end'

}

},

end: { type: 'final' }

}

});
interpret(parent).start();