refac: add more utils and types
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1 changed files with 37 additions and 24 deletions
61
fsm.ts
61
fsm.ts
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@ -3,41 +3,44 @@ type StateTransitions<Context> = WeakMap<
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WeakSet<State<Context>>
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WeakSet<State<Context>>
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>;
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>;
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type StateName = string;
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type StateOrName<Context> = State<Context> | StateName;
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export const _states = Symbol("states");
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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 _stateTransitions = Symbol("state transitions");
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export const _prevState = Symbol("previous state");
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export const _prevState = Symbol("previous state");
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export const _currState = Symbol("current state");
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export const _currState = Symbol("current state");
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export class StateMachineBuilder<Context> {
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export class StateMachineBuilder<Context> {
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[_states]: Map<string, Actions<Context>>;
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[_states]: Map<StateName, Actions<Context>>;
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[_stateTransitions]: Array<[string, Array<string>]> | undefined;
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[_stateTransitions]: Array<[StateName, Array<StateName>]> | undefined;
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constructor() {
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constructor() {
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this[_states] = new Map();
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this[_states] = new Map();
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}
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}
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withTransitions(transitions: Array<[string, Array<string>]>) {
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withTransitions(transitions: Array<[StateName, Array<StateName>]>) {
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this[_stateTransitions] = transitions;
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this[_stateTransitions] = transitions;
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return this;
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return this;
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}
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}
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withStates(names: string[], actions?: Actions<Context>) {
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withStates(names: StateName[], actions?: Actions<Context>) {
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names.forEach((name) => this.addStateUnchecked(name, actions));
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names.forEach((name) => this.addStateUnchecked(name, actions));
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return this;
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return this;
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}
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}
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withState(name: string, actions?: Actions<Context>) {
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withState(name: StateName, actions?: Actions<Context>) {
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this.addStateUnchecked(name, actions);
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this.addStateUnchecked(name, actions);
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return this;
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return this;
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}
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}
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private addStateUnchecked(name: string, actions?: Actions<Context>) {
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private addStateUnchecked(name: StateName, actions?: Actions<Context>) {
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const oldActions = this[_states].get(name);
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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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return this[_states].set(name, { ...oldActions, ...actions });
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}
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}
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build(currentStateName: string) {
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build(currentStateName: StateName) {
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const states = this.buildStates();
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const states = this.buildStates();
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const transitions = this.buildTransitions(states);
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const transitions = this.buildTransitions(states);
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const currState = validStateFromName(states, currentStateName);
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const currState = validStateFromName(states, currentStateName);
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@ -81,9 +84,9 @@ export class StateMachine<Context> {
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this[_currState] = currentState;
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this[_currState] = currentState;
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}
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}
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async changeState(sourceState: string | State<Context>, context?: Context) {
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async changeState(sourceState: StateOrName<Context>, context?: Context) {
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const fromState = validState(this[_currState]);
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const fromState = validState(this[_currState]);
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const toState = validState(normalizeState(this[_states], sourceState));
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const toState = validNormalizedState(this[_states], sourceState);
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if (
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if (
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!this.hasTransition(toState) ||
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!this.hasTransition(toState) ||
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@ -100,11 +103,11 @@ export class StateMachine<Context> {
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this[_prevState] = fromState;
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this[_prevState] = fromState;
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}
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}
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hasTransition(to: string | State<Context>) {
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hasTransition(to: StateOrName<Context>) {
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return hasTransition(
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return hasTransition(
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this[_stateTransitions],
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this[_stateTransitions],
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this[_currState],
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this[_currState],
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validState(normalizeState(this[_states], to)),
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validNormalizedState(this[_states], to),
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);
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);
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}
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}
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@ -123,25 +126,25 @@ interface Actions<Context> {
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beforeExit?(
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beforeExit?(
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fromState: State<Context>,
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fromState: State<Context>,
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toState: State<Context>,
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toState: State<Context>,
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context: Context,
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context?: Context,
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): boolean;
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): boolean;
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onEntry?(
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onEntry?(
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fromState: State<Context>,
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fromState: State<Context>,
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toState: State<Context>,
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toState: State<Context>,
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context: Context,
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context?: Context,
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): Promise<void> | void;
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): Promise<void> | void;
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}
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}
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export class State<Context> {
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export class State<Context> {
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[_stateActions]: Actions<Context>;
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[_stateActions]: Actions<Context>;
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[_stateName]: string;
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[_stateName]: StateName;
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get name(): string {
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get name(): StateName {
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return this[_stateName];
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return this[_stateName];
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}
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}
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constructor(name: string, actions: Actions<Context> = {}) {
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constructor(name: StateName, actions: Actions<Context> = {}) {
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this[_stateName] = name;
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this[_stateName] = name;
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this[_stateActions] = actions;
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this[_stateActions] = actions;
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}
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}
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@ -149,7 +152,7 @@ export class State<Context> {
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async entry(
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async entry(
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fromState: State<Context>,
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fromState: State<Context>,
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toState: State<Context>,
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toState: State<Context>,
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context: Context,
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context?: Context,
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) {
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) {
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const action = this[_stateActions].onEntry;
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const action = this[_stateActions].onEntry;
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if (isFn(action)) {
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if (isFn(action)) {
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@ -171,21 +174,31 @@ export class State<Context> {
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}
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}
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}
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}
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function stateFromName<Context>(states: State<Context>[], name: string) {
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function validNormalizedState<Context>(
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return states.find((state) => state.name === name);
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states: State<Context>[],
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}
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state: StateOrName<Context>,
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) {
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function validStateFromName<Context>(states: State<Context>[], name: string) {
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return validState<Context>(normalizeState(states, state));
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return validState<Context>(stateFromName(states, name));
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}
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}
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function normalizeState<Context>(
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function normalizeState<Context>(
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states: State<Context>[],
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states: State<Context>[],
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state: string | State<Context>,
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state: StateOrName<Context>,
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): State<Context> | undefined {
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): State<Context> | undefined {
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return isStr(state) ? stateFromName(states, state) : state;
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return isStr(state) ? stateFromName(states, state) : state;
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}
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}
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function validStateFromName<Context>(
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states: State<Context>[],
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name: StateName,
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) {
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return validState<Context>(stateFromName(states, name));
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}
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function stateFromName<Context>(states: State<Context>[], name: StateName) {
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return states.find((state) => state.name === name);
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}
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function validState<Context>(val: unknown): State<Context> {
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function validState<Context>(val: unknown): State<Context> {
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if (!isState<Context>(val)) {
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if (!isState<Context>(val)) {
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throw new TypeError("an instance of State class is expected");
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throw new TypeError("an instance of State class is expected");
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