feat: add actions
This commit is contained in:
parent
0d377ba222
commit
8f3fd1337b
2 changed files with 185 additions and 89 deletions
21
fsm.test.ts
21
fsm.test.ts
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@ -208,3 +208,24 @@ Deno.test("should reuse one builder for many entities", () => {
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);
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}
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});
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Deno.test("should trigger builded transition actions", async () => {
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const states = ["locked", "unlocked"] as const;
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const [locked, unlocked] = states;
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const sm = new fsm.StateMachineBuilder()
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.withStates([locked, unlocked])
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.withTransitions([
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[locked, { coin: unlocked }],
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[unlocked, { push: locked }],
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])
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.build(locked);
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const [lockedState, unlockedState] = sm[fsm._states];
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assertEquals(await sm.trigger("coin", {}), unlockedState);
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assertEquals(await sm.trigger("coin", {}), unlockedState);
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assertEquals(await sm.trigger("push", {}), lockedState);
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assertEquals(await sm.trigger("push", {}), lockedState);
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});
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253
fsm.ts
253
fsm.ts
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@ -1,64 +1,104 @@
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type StateTransitions<Context, StateName extends string> = WeakMap<
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State<Context, StateName>,
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WeakSet<State<Context, StateName>>
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type StateTransitions<Ctx, SN extends string> = WeakMap<
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State<Ctx, SN>,
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WeakSet<State<Ctx, SN>>
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>;
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type StateOrName<Context, StateName extends string> =
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| State<Context, StateName>
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| StateName;
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type StateOrName<Ctx, SN extends string> =
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| State<Ctx, SN>
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| SN;
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type SourceTransitions<SN extends string> = Array<[SN, Array<SN>]>;
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type SourceNamedTransitions<SN extends string> = Array<
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[SN, Record<string, SN>]
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>;
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type SourceActions<SN extends string> = Record<string, Array<[SN, SN]>>;
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export const _states = Symbol("states");
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export const _stateTransitions = Symbol("state transitions");
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export const _prevState = Symbol("previous state");
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export const _currState = Symbol("current state");
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const _transitions = Symbol("transitions");
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const _actions = Symbol("actions");
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const _prevState = Symbol("previous state");
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const _currState = Symbol("current state");
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export class StateMachineBuilder<Context, StateName extends string = string> {
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[_states]: Map<StateName, Events<Context, StateName>>;
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export class StateMachineBuilder<Ctx, SN extends string = string> {
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[_states]: Map<SN, Events<Ctx, SN>>;
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[_stateTransitions]: Array<[StateName, Array<StateName>]> | undefined;
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[_transitions]: SourceTransitions<SN> | undefined;
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[_actions]: SourceActions<SN> | undefined;
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constructor() {
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this[_states] = new Map();
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}
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withTransitions(transitions: Array<[StateName, Array<StateName>]>) {
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this[_stateTransitions] = transitions;
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withTransitions(
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sourceTransitions: SourceTransitions<SN> | SourceNamedTransitions<SN>,
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) {
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const [t, a] =
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(sourceTransitions as Array<[SN, Array<SN> | Record<string, SN>]>)
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.reduce(
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([transitions, actions], [fromState, sources]) => {
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const toStates = Array.isArray(sources)
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? sources
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: Object.values(sources);
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transitions.push([fromState, toStates]);
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if (!Array.isArray(sources)) {
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Object.entries(sources).forEach(([actionName, toState]) => {
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const actionTransitions = actions[actionName] || [];
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actions[actionName] = [
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...actionTransitions,
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[fromState, toState],
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];
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});
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}
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return [transitions, actions];
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},
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[[], {}] as [SourceTransitions<SN>, SourceActions<SN>],
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);
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this[_transitions] = t;
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this[_actions] = a;
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return this;
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}
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withStates(names: StateName[], actions?: Events<Context, StateName>) {
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withStates(names: SN[], actions?: Events<Ctx, SN>) {
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names.forEach((name) => this.addStateUnchecked(name, actions));
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return this;
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}
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withState(name: StateName, actions?: Events<Context, StateName>) {
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withState(name: SN, actions?: Events<Ctx, SN>) {
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this.addStateUnchecked(name, actions);
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return this;
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}
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private addStateUnchecked(
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name: StateName,
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actions?: Events<Context, StateName>,
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name: SN,
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actions?: Events<Ctx, SN>,
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) {
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const oldActions = this[_states].get(name);
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return this[_states].set(name, { ...oldActions, ...actions });
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}
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build(currentStateName: StateName) {
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build(currentStateName: SN) {
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const states = this.buildStates();
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const transitions = this.buildTransitions(states);
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const actions = this.buildActions(states);
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const currState = validStateFromName(states, currentStateName);
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return new StateMachine<Context, StateName>(states, transitions, currState);
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return new StateMachine<Ctx, SN>(currState, states, {
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transitions,
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actions,
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});
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}
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private buildStates() {
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return Array.from(this[_states].entries()).map((params) =>
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new State(...params)
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);
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return Array.from(this[_states].entries())
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.map((params) => new State(...params));
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}
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private buildTransitions(states: State<Context, StateName>[]) {
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const sourceTransitions = this[_stateTransitions] || [];
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private buildTransitions(states: State<Ctx, SN>[]) {
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const sourceTransitions = this[_transitions];
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if (!sourceTransitions) return undefined;
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return new WeakMap(
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sourceTransitions.map(([from, toStates]) => [
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@ -67,32 +107,63 @@ export class StateMachineBuilder<Context, StateName extends string = string> {
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]),
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);
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}
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private buildActions(states: State<Ctx, SN>[]): Actions<Ctx, SN> | undefined {
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const actions = this[_actions];
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if (!actions) return undefined;
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return new Map(
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Object.entries(actions).map(([actionName, variants]) => [
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actionName,
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variants.map(([fromState, toState]) => [
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validStateFromName(states, fromState),
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validStateFromName(states, toState),
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]),
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]),
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);
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}
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}
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export class StateMachine<Context, StateName extends string = string> {
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[_states]: State<Context, StateName>[];
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interface StateMachineOpts<Ctx, SN extends string> {
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transitions?: StateTransitions<Ctx, SN>;
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actions?: Actions<Ctx, SN>;
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}
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[_stateTransitions]: StateTransitions<Context, StateName>;
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type Actions<Ctx, SN extends string> = Map<
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string,
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Array<[State<Ctx, SN>, State<Ctx, SN>]>
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>;
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[_prevState]: State<Context, StateName> | undefined;
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export class StateMachine<Ctx, SN extends string = string> {
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[_states]: State<Ctx, SN>[];
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[_currState]: State<Context, StateName>;
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[_transitions]: StateTransitions<Ctx, SN>;
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[_actions]: Actions<Ctx, SN>;
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[_prevState]: State<Ctx, SN> | undefined;
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[_currState]: State<Ctx, SN>;
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get currentState() {
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return this[_currState];
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}
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constructor(
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states: State<Context, StateName>[],
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transitions: StateTransitions<Context, StateName>,
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currentState: State<Context, StateName>,
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currentState: State<Ctx, SN>,
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states: State<Ctx, SN>[],
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{ transitions, actions }: StateMachineOpts<Ctx, SN>,
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) {
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this[_states] = states;
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this[_stateTransitions] = transitions;
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this[_currState] = currentState;
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this[_states] = states;
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this[_transitions] = transitions || new Map();
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this[_actions] = actions || new Map();
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}
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async tryChangeState(
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state: StateOrName<Context, StateName>,
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context: Context,
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state: StateOrName<Ctx, SN>,
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context: Ctx,
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) {
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const fromState = validState<Context, StateName>(this[_currState]);
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const fromState = validState<Ctx, SN>(this.currentState);
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const toState = validNormalizedState(this[_states], state);
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if (
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@ -112,64 +183,76 @@ export class StateMachine<Context, StateName extends string = string> {
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return this[_currState];
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}
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maybeChangeState(state: StateOrName<Context, StateName>, context: Context) {
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maybeChangeState(state: StateOrName<Ctx, SN>, context: Ctx) {
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return this.tryChangeState(state, context).catch(() => null);
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}
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hasTransition(to: StateOrName<Context, StateName>) {
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hasTransition(to: StateOrName<Ctx, SN>) {
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return hasTransition(
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this[_stateTransitions],
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this[_transitions],
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this[_currState],
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validNormalizedState(this[_states], to),
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);
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}
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allowedTransitionStates() {
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const fromState = validState(this[_currState]);
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return this[_states].filter(
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hasTransition.bind(null, this[_stateTransitions], fromState),
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hasTransition.bind(null, this[_transitions], this[_currState]),
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);
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}
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allowedTransitionStateNames() {
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return this.allowedTransitionStates().map(String);
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}
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trigger(actionName: string, context: Ctx) {
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const currState = this[_currState];
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const variants = this[_actions]?.get(actionName);
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if (!variants) return currState;
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const [, toState] =
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variants.find(([fromState]) => fromState === currState) || [];
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if (!toState) return currState;
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return this.tryChangeState(toState, context);
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}
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}
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const _stateName = Symbol("state name");
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const _stateEvents = Symbol("state events");
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interface Events<Context, StateName extends string> {
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interface Events<Ctx, SN extends string> {
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beforeExit?(
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fromState: State<Context, StateName>,
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toState: State<Context, StateName>,
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context: Context,
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fromState: State<Ctx, SN>,
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toState: State<Ctx, SN>,
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context: Ctx,
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): boolean;
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onEntry?(
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fromState: State<Context, StateName>,
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toState: State<Context, StateName>,
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context: Context,
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fromState: State<Ctx, SN>,
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toState: State<Ctx, SN>,
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context: Ctx,
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): Promise<void> | void;
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}
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export class State<Context, StateName extends string = string> {
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[_stateEvents]: Events<Context, StateName>;
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export class State<Ctx, SN extends string = string> {
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[_stateEvents]: Events<Ctx, SN>;
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[_stateName]: StateName;
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[_stateName]: SN;
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get name(): StateName {
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get name(): SN {
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return this[_stateName];
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}
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constructor(name: StateName, events: Events<Context, StateName> = {}) {
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constructor(name: SN, events: Events<Ctx, SN> = {}) {
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this[_stateName] = name;
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this[_stateEvents] = events;
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}
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async entry(
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fromState: State<Context, StateName>,
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toState: State<Context, StateName>,
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context: Context,
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fromState: State<Ctx, SN>,
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toState: State<Ctx, SN>,
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context: Ctx,
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) {
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const event = this[_stateEvents].onEntry;
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if (isFn(event)) {
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@ -177,11 +260,7 @@ export class State<Context, StateName extends string = string> {
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}
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}
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exit(
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fromState: State<Context, StateName>,
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toState: State<Context, StateName>,
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context: Context,
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) {
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exit(fromState: State<Ctx, SN>, toState: State<Ctx, SN>, context: Ctx) {
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const event = this[_stateEvents].beforeExit;
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return isFn(event) ? event(fromState, toState, context) : true;
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}
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@ -195,53 +274,49 @@ export class State<Context, StateName extends string = string> {
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}
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}
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function validNormalizedState<Context, StateName extends string>(
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states: State<Context, StateName>[],
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state: StateOrName<Context, StateName>,
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function validNormalizedState<Ctx, SN extends string>(
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states: State<Ctx, SN>[],
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state: StateOrName<Ctx, SN>,
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) {
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return validState<Context, StateName>(normalizeState(states, state));
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return validState<Ctx, SN>(normalizeState(states, state));
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}
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function normalizeState<Context, StateName extends string>(
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states: State<Context, StateName>[],
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state: StateOrName<Context, StateName>,
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): State<Context, StateName> | undefined {
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function normalizeState<Ctx, SN extends string>(
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states: State<Ctx, SN>[],
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state: StateOrName<Ctx, SN>,
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): State<Ctx, SN> | undefined {
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return isStr(state) ? stateFromName(states, state) : state;
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}
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function validStateFromName<Context, StateName extends string>(
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states: State<Context, StateName>[],
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name: StateName,
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function validStateFromName<Ctx, SN extends string>(
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states: State<Ctx, SN>[],
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name: SN,
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) {
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return validState<Context, StateName>(stateFromName(states, name));
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return validState<Ctx, SN>(stateFromName(states, name));
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}
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function stateFromName<Context, StateName extends string>(
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states: State<Context, StateName>[],
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name: StateName,
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function stateFromName<Ctx, SN extends string>(
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states: State<Ctx, SN>[],
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name: SN,
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) {
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return states.find((state) => state.name === name);
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}
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function validState<Context, StateName extends string>(
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val: unknown,
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): State<Context, StateName> {
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if (!isState<Context, StateName>(val)) {
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function validState<Ctx, SN extends string>(val: unknown): State<Ctx, SN> {
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if (!isState<Ctx, SN>(val)) {
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throw new TypeError("an instance of State class is expected");
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}
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return val;
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}
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function isState<Context, StateName extends string>(
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val: unknown,
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): val is State<Context, StateName> {
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function isState<Ctx, SN extends string>(val: unknown): val is State<Ctx, SN> {
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return val instanceof State;
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}
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function hasTransition<Context, StateName extends string>(
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transitions: StateTransitions<Context, StateName>,
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from: State<Context, StateName>,
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to: State<Context, StateName>,
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function hasTransition<Ctx, SN extends string>(
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transitions: StateTransitions<Ctx, SN>,
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from: State<Ctx, SN>,
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to: State<Ctx, SN>,
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) {
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return transitions.get(from)?.has(to) || false;
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}
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