Type Guards

Type Safety Everywhere

Cool autocomplete and type safety scenarios:

import { PromiseMachine, PromiseMachineEvent, createPromiseMachine } from 'matchina'

const delay = (ms: number) => new Promise((resolve) => setTimeout(resolve, ms))

const slowAddingMachine = createPromiseMachine(async (a: number, b: number, t: number = 1000) => {
  await delay(t)
  return a + b
})

slowAddingMachine.send('execute', 1, 2)

const lastChange = slowAddingMachine.getChange()

if (lastChange.to.key === 'Resolved') {
  const sum = lastChange.to.data
}

lastChange.to.match({
  Pending: ([a, b, t]) => {
    console.log(a, b, a + b)
  },
  Rejected: (err) => {
    console.log(err.name, err.message)
  }
}, false)

lastChange.from.as('Rejected').key === 'Rejected'

if (lastChange.to.is('Pending')) {
  const [a, b, t] = lastChange.to.data
}

lastChange.match({
  execute: (a, b, t=1000) => {
    console.log(a, b, t)
  },
  reject: (err) => {
    console.log(err.name, err.message)
  }
}, false)

On states

Factory autocompletes states types
State Creator autocompletes parameters
State autocompletes key
State autocompletes data
match autocompletes state types
match handler autocompletes state properties

On state machines

transition config autocompletes state keys
transition config autocompletes transition type and from properties
autocomplete available states
api autocompletes state types
api autocompletes transition params

On state machine events

event autocompletes event type, to, from, and params
event.match autocompletes event type
event.match handler autocompletes event params
type assert matching to.key, from.key and event type

On hooks and typeguards

Code Snippets

114 lines, 2385 chars

type type MyStateData = {
    Idle: undefined;
    Foo: (foo: string) => {
        foo: string;
    };
    Bar: (bar: number) => {
        bar: number;
    };
}MyStateData = {
  type Idle: undefinedIdle: undefined;
  type Foo: (foo: string) => {
    foo: string;
}Foo: (foo: stringfoo: string) => {
      foo: stringfoo: string;
  };
  type Bar: (bar: number) => {
    bar: number;
}Bar: (bar: numberbar: number) => {
      bar: numberbar: number;
  };
}
type type MyStates = {
    Idle: () => StateMatchbox<"Idle", MyStateData>;
    Foo: (foo: string) => StateMatchbox<"Foo", MyStateData>;
    Bar: (bar: number) => StateMatchbox<"Bar", MyStateData>;
}MyStates = type States<Specs extends SpecRecord> = { [T in string & keyof Specs]: CreateState<Specs, T>; }States<type MyStateData = {
    Idle: undefined;
    Foo: (foo: string) => {
        foo: string;
    };
    Bar: (bar: number) => {
        bar: number;
    };
}MyStateData>

const const states: MyStatesstates: type MyStates = {
    Idle: () => StateMatchbox<"Idle", MyStateData>;
    Foo: (foo: string) => StateMatchbox<"Foo", MyStateData>;
    Bar: (bar: number) => StateMatchbox<"Bar", MyStateData>;
}MyStates = defineStates<MyStateData>(config: MyStateData): States<MyStateData>defineStates<type MyStateData = {
    Idle: undefined;
    Foo: (foo: string) => {
        foo: string;
    };
    Bar: (bar: number) => {
        bar: number;
    };
}MyStateData>( {
  type Idle: undefinedIdle: var undefinedundefined,
  type Foo: (foo: string) => {
    foo: string;
}Foo: (foo: stringfoo: string) => ({ foo: stringfoo }),
  type Bar: (bar: number) => {
    bar: number;
}Bar: (bar: numberbar: number) => ({ bar: numberbar })
})

type type Transitions = object & {
    Idle?: {
        [x: string]: FactoryMachineTransition<MyStates, "Idle", string> | undefined;
    } | undefined;
    Foo?: {
        [x: string]: FactoryMachineTransition<MyStates, "Foo", string> | undefined;
    } | undefined;
    Bar?: {
        ...;
    } | undefined;
} & {
    ...;
}Transitions  = 
type FactoryMachineTransitions<SF extends AnyStatesFactory> = object & { [FromStateKey in string & keyof SF]?: {
    [x: string]: FactoryMachineTransition<SF, FromStateKey, string> | undefined;
} | undefined; }FactoryMachineTransitions<type MyStates = {
    Idle: () => StateMatchbox<"Idle", MyStateData>;
    Foo: (foo: string) => StateMatchbox<"Foo", MyStateData>;
    Bar: (bar: number) => StateMatchbox<"Bar", MyStateData>;
}MyStates> &
{
  readonly type Idle: {
    readonly start: "Foo";
}Idle: {
      readonly start: "Foo"start: "Foo";
  };
  readonly type Foo: {
    readonly toggle: "Bar";
    readonly foo: (foo?: string) => MyStates["Foo"];
}Foo: {
      readonly toggle: "Bar"toggle: "Bar";
      readonly foo: (foo?: string) => MyStates["Foo"]foo: (foo: string | undefinedfoo?: string) => type MyStates = {
    Idle: () => StateMatchbox<"Idle", MyStateData>;
    Foo: (foo: string) => StateMatchbox<"Foo", MyStateData>;
    Bar: (bar: number) => StateMatchbox<"Bar", MyStateData>;
}MyStates['Foo']
  };
  readonly  type Bar: {
    readonly toggle: "Foo";
    readonly increment: (bar: number) => (ev: any) => MyStates["Bar"];
}Bar: {
    readonly toggle: "Foo"toggle: "Foo";
    readonly increment: (bar: number) => (ev: any) => MyStates["Bar"]increment: (bar: numberbar: number) => (ev: anyev: any) => type MyStates = {
    Idle: () => StateMatchbox<"Idle", MyStateData>;
    Foo: (foo: string) => StateMatchbox<"Foo", MyStateData>;
    Bar: (bar: number) => StateMatchbox<"Bar", MyStateData>;
}MyStates['Bar'];
  }
}

const const transitions: Transitionstransitions: type Transitions = object & {
    Idle?: {
        [x: string]: FactoryMachineTransition<MyStates, "Idle", string> | undefined;
    } | undefined;
    Foo?: {
        [x: string]: FactoryMachineTransition<MyStates, "Foo", string> | undefined;
    } | undefined;
    Bar?: {
        ...;
    } | undefined;
} & {
    ...;
}Transitions = {
  type Idle: {
    [x: string]: FactoryMachineTransition<MyStates, "Idle", string> | undefined;
} & {
    readonly start: "Foo";
}Idle: {
    start: "Foo"start: 'Foo'
  },
  type Foo: {
    [x: string]: FactoryMachineTransition<MyStates, "Foo", string> | undefined;
} & {
    readonly toggle: "Bar";
    readonly foo: (foo?: string) => MyStates["Foo"];
}Foo: {
    toggle: "Bar"toggle: 'Bar',
    foo: (foo?: string) => MyStates["Foo"]foo: (foo: string | undefinedfoo = 'foo') => const states: MyStatesstates.type Foo: (foo: string) => StateMatchbox<"Foo", MyStateData>Foo(`my-${foo: stringfoo}`) as any,      
  },
  type Bar: {
    [x: string]: FactoryMachineTransition<MyStates, "Bar", string> | undefined;
} & {
    readonly toggle: "Foo";
    readonly increment: (bar: number) => (ev: any) => MyStates["Bar"];
}Bar: {
    toggle: "Foo"toggle: 'Foo',
    increment: (bar: number) => (ev: any) => MyStates["Bar"]increment: (bar: numberbar: number) => (ev: anyev: any) => 
      const states: MyStatesstates.type Bar: (bar: number) => StateMatchbox<"Bar", MyStateData>Barev: any(ev.anyfrom.anydata.anybar + bar: numberbar) as any
  }
}

const const machine: FactoryMachine<{
    states: MyStates;
    transitions: Transitions;
}>machine = createFactoryMachine<MyStates, Transitions, {
    states: MyStates;
    transitions: Transitions;
}, FactoryMachineEvent<{
    states: MyStates;
    transitions: Transitions;
}>>(states: MyStates, transitions: Transitions, init: "Idle" | ... 2 more ... | StateMatchbox<...>): FactoryMachine<{
    ...;
}>createFactoryMachine<type MyStates = {
    Idle: () => StateMatchbox<"Idle", MyStateData>;
    Foo: (foo: string) => StateMatchbox<"Foo", MyStateData>;
    Bar: (bar: number) => StateMatchbox<"Bar", MyStateData>;
}MyStates, type Transitions = object & {
    Idle?: {
        [x: string]: FactoryMachineTransition<MyStates, "Idle", string> | undefined;
    } | undefined;
    Foo?: {
        [x: string]: FactoryMachineTransition<MyStates, "Foo", string> | undefined;
    } | undefined;
    Bar?: {
        ...;
    } | undefined;
} & {
    ...;
}Transitions>(
  const states: MyStatesstates, 
  const transitions: Transitionstransitions, 
  'Idle'
)

const machine: FactoryMachine<{
    states: MyStates;
    transitions: Transitions;
}>machine.FactoryMachine<{ states: MyStates; transitions: Transitions; }>.states: MyStatesstates.BBarar(1).data: {
    bar: number;
}data.bar: numberbar === 1

// const change = machine.getChange()
// const { type, from: {key: fromKey}, to: { key: toKey } } = change


const const slowAddingMachine: PromiseMachine<(a: number, b: number, t?: number) => Promise<number>>slowAddingMachine = createPromiseMachine<(a: number, b: number, t?: number) => Promise<number>>(makePromise?: ((a: number, b: number, t?: number) => Promise<number>) | undefined): PromiseMachine<(a: number, b: number, t?: number) => Promise<number>>createPromiseMachine(async (a: numbera: number, b: numberb: number, t: numbert: number = 1000) => {
  await function delay(ms: number): Promise<unknown>delay(t: numbert)
  return a: numbera + b: numberb
})

const slowAddingMachine: PromiseMachine<(a: number, b: number, t?: number) => Promise<number>>slowAddingMachine.StateMachine<FactoryMachineEvent<{ states: PromiseStates<(a: number, b: number, t?: number) => Promise<number>, Error>; transitions: PromiseTransitions; }>>.send: (type: "execute" | "resolve" | "reject", ...params: (any[] & [a: number, b: number, t?: number | undefined]) | (any[] & [data: number]) | (any[] & [error: Error])) => voidsend('execute', 1, 2)
const const api: {
    readonly execute: (...args: any[] & [a: number, b: number, t?: number | undefined]) => void;
    readonly resolve: (...args: any[] & [data: number]) => void;
    readonly reject: (...args: any[] & [error: Error]) => void;
} & objectapi = createApi<PromiseMachine<(a: number, b: number, t?: number) => Promise<number>>, keyof PromiseTransitions>(machine: PromiseMachine<(a: number, b: number, t?: number) => Promise<...>>, filterStateKey?: keyof PromiseTransitions | undefined): FactoryMachineApi<PromiseMachine<...>>createApiconst slowAddingMachine: PromiseMachine<(a: number, b: number, t?: number) => Promise<number>>(slowAddingMachine)
const api: {
    readonly execute: (...args: any[] & [a: number, b: number, t?: number | undefined]) => void;
    readonly resolve: (...args: any[] & [data: number]) => void;
    readonly reject: (...args: any[] & [error: Error]) => void;
} & objectapi.rreject
resolveeject(new var Error: ErrorConstructor
new (message?: string, options?: ErrorOptions) => Error (+1 overload)Error('test'))

const const lastChange: FactoryMachineEvent<{
    states: PromiseStates<(a: number, b: number, t?: number) => Promise<number>, Error>;
    transitions: PromiseTransitions;
}>lastChange = const slowAddingMachine: PromiseMachine<(a: number, b: number, t?: number) => Promise<number>>slowAddingMachine.StateMachine<FactoryMachineEvent<{ states: PromiseStates<(a: number, b: number, t?: number) => Promise<number>, Error>; transitions: PromiseTransitions; }>>.getChange(): FactoryMachineEvent<{
    states: PromiseStates<(a: number, b: number, t?: number) => Promise<number>, Error>;
    transitions: PromiseTransitions;
}>getChange()


const lastChange: FactoryMachineEvent<{
    states: PromiseStates<(a: number, b: number, t?: number) => Promise<number>, Error>;
    transitions: PromiseTransitions;
}>lastChange.to: ({
    key: "Pending";
    data: [a: number, b: number, t?: number | undefined];
} & MemberExtensionsFromDataSpecs<PromiseStateCreators<(a: number, b: number, t?: number) => Promise<number>, Error>, "key">) | ({
    ...;
} & MemberExtensionsFromDataSpecs<...>) | ({
    ...;
} & MemberExtensionsFromDataSpecs<...>)to.MemberExtensionsFromDataSpecs<DataSpecs, TagProp extends string>.match: MatchMemberData
<void, false>(cases: Partial<Cases<MemberData<PromiseStateCreators<(a: number, b: number, t?: number) => Promise<number>, Error>>, void> & {
    ...;
}>, exhaustive?: false | undefined) => voidmatch({
  Pending?: ((value: [a: number, b: number, t?: number | undefined]) => void) | undefinedPending: ([a: numbera, b: numberb, t: number | undefinedt]) => {
    
  },
  Rejected?: ((value: Error) => void) | undefinedRejected: (err: Errorerr) => {
    var console: Consoleconsole.Console.log(...data: any[]): void[MDN Reference](https://developer.mozilla.org/docs/Web/API/console/log_static)log(err: Errorerr.Error.name: stringname, err: Errorerr.Error.message: stringmessage)
  }
}, false)
const { const from: ({
    key: "Pending";
    data: [a: number, b: number, t?: number | undefined];
} & MemberExtensionsFromDataSpecs<PromiseStateCreators<(a: number, b: number, t?: number) => Promise<number>, Error>, "key">) | ({
    ...;
} & MemberExtensionsFromDataSpecs<...>)from } = const lastChange: FactoryMachineEvent<{
    states: PromiseStates<(a: number, b: number, t?: number) => Promise<number>, Error>;
    transitions: PromiseTransitions;
}>lastChange

if (matchChange<FactoryMachineEvent<{
    states: PromiseStates<(a: number, b: number, t?: number) => Promise<number>, Error>;
    transitions: PromiseTransitions;
}>, "execute" | ... 2 more ... | undefined, "Idle" | ... 1 more ... | undefined, "Rejected">(changeEvent: FactoryMachineEvent<...>, ...rest: [type?: ...] | [filter: ...]): changeEvent is StateMachineEvent<...> & ... 2 more ... & {
    ...;
}matchChange(
  const lastChange: FactoryMachineEvent<{
    states: PromiseStates<(a: number, b: number, t?: number) => Promise<number>, Error>;
    transitions: PromiseTransitions;
}>lastChange,
  {
    to?: "Rejected" | undefinedto: 'Rejected'
  })) {
    const lastChange: FactoryMachineTransitionEvent<{
    states: PromiseStates<(a: number, b: number, t?: number) => Promise<number>, Error>;
    transitions: PromiseTransitions;
}, "Pending", "reject", "Rejected">lastChange.type: "reject"type = 'reject'
  }

const lastChange: FactoryMachineEvent<{
    states: PromiseStates<(a: number, b: number, t?: number) => Promise<number>, Error>;
    transitions: PromiseTransitions;
}>lastChange.match: MatchInvocation
<void, false>(cases: Partial<InvocationCases<FlatMemberUnion<StateEventTransitionSenders<{
    states: PromiseStates<(a: number, b: number, t?: number) => Promise<number>, Error>;
    transitions: PromiseTransitions;
}>>, void> & {
    ...;
}>, exhaustive?: false | undefined) => voidmatch({
  execute?: ((...params: any[] & [a: number, b: number, t?: number | undefined]) => void) | undefinedexecute: (a: numbera, b: numberb, t: number | undefinedt=1000) => {
    var console: Consoleconsole.Console.log(...data: any[]): void[MDN Reference](https://developer.mozilla.org/docs/Web/API/console/log_static)log(a: numbera, b: numberb, t: numbert)
  },
  reject?: ((...params: any[] & [error: Error]) => void) | undefinedreject: (err: Errorerr) => {
    var console: Consoleconsole.Console.log(...data: any[]): void[MDN Reference](https://developer.mozilla.org/docs/Web/API/console/log_static)log(err: Errorerr.Error.name: stringname, err: Errorerr.Error.message: stringmessage)
  }
}, false)

if const lastChange: FactoryMachineEvent<{
    states: PromiseStates<(a: number, b: number, t?: number) => Promise<number>, Error>;
    transitions: PromiseTransitions;
}>(lastChange.to: ({
    key: "Pending";
    data: [a: number, b: number, t?: number | undefined];
} & MemberExtensionsFromDataSpecs<PromiseStateCreators<(a: number, b: number, t?: number) => Promise<number>, Error>, "key">) | ({
    ...;
} & MemberExtensionsFromDataSpecs<...>) | ({
    ...;
} & MemberExtensionsFromDataSpecs<...>)to.MemberExtensionsFromDataSpecs<DataSpecs, TagProp extends string>.is: <"Pending">(key: "Pending") => this is MemberFromDataSpecs<T, DataSpecs, TagProp>is('Pending')) {
  const [const a: numbera, const b: numberb, const t: number | undefinedt] = const lastChange: FactoryMachineEvent<{
    states: PromiseStates<(a: number, b: number, t?: number) => Promise<number>, Error>;
    transitions: PromiseTransitions;
}>lastChange.to: {
    key: "Pending";
    data: [a: number, b: number, t?: number | undefined];
} & MemberExtensionsFromDataSpecs<PromiseStateCreators<(a: number, b: number, t?: number) => Promise<number>, Error>, "key">to.data: [a: number, b: number, t?: number | undefined]data
}

const slowAddingMachine: PromiseMachine<(a: number, b: number, t?: number) => Promise<number>>slowAddingMachine.FactoryMachine<{ states: PromiseStates<(a: number, b: number, t?: number) => Promise<number>, Error>; transitions: PromiseTransitions; }>.states: PromiseStates<(a: number, b: number, t?: number) => Promise<number>, Error>states.type Idle: () => StateMatchbox<"Idle", PromiseStateCreators<(a: number, b: number, t?: number) => Promise<number>, Error>>Idle().key: "Idle"key

const { const type: "execute" | "resolve" | "reject"type, from: ({
    key: "Pending";
    data: [a: number, b: number, t?: number | undefined];
} & MemberExtensionsFromDataSpecs<PromiseStateCreators<(a: number, b: number, t?: number) => Promise<number>, Error>, "key">) | ({
    ...;
} & MemberExtensionsFromDataSpecs<...>)from: {key: "Idle" | "Pending"key: const fromKey: "Idle" | "Pending"fromKey}, to: ({
    key: "Pending";
    data: [a: number, b: number, t?: number | undefined];
} & MemberExtensionsFromDataSpecs<PromiseStateCreators<(a: number, b: number, t?: number) => Promise<number>, Error>, "key">) | ({
    ...;
} & MemberExtensionsFromDataSpecs<...>) | ({
    ...;
} & MemberExtensionsFromDataSpecs<...>)to: { key: "Pending" | "Rejected" | "Resolved"key: const toKey: "Pending" | "Rejected" | "Resolved"toKey } } = const lastChange: FactoryMachineEvent<{
    states: PromiseStates<(a: number, b: number, t?: number) => Promise<number>, Error>;
    transitions: PromiseTransitions;
}>lastChange