state pattern

Author: 1709abhishek

state-pattern/IdleState.ts

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+import { VendingMachine } from "./VendingMachine";
+import { VendingState } from "./VendingState";
+import { WorkingState } from "./WorkingState";
+
+
+export class IdleState extends VendingState {
+  public insertCoin(machine: VendingMachine): VendingState {
+    console.log('Coin inserted, transitioning to WorkingState');
+    return new WorkingState();
+  }
+  public dispense(machine: VendingMachine): void {
+    console.log('Cannot dispense, no coin inserted');
+  }
+}

state-pattern/VendingMachine.ts

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+import { VendingState } from './VendingState';
+
+export class VendingMachine {
+  private state: VendingState;
+
+  constructor(initialState: VendingState) {
+    this.state = initialState;
+  }
+
+  public setState(state: VendingState): void {
+    this.state = state;
+  }
+
+  public insertCoin(): void {
+    this.state = this.state.insertCoin(this);
+  }
+
+  public dispense(): void {
+    this.state.dispense(this);
+  }
+
+  public getState(): VendingState {
+    return this.state;
+  }
+}

state-pattern/VendingState.ts

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+import { VendingMachine } from "./VendingMachine";
+
+
+export abstract class VendingState{
+  abstract insertCoin(machine: VendingMachine): VendingState;
+  abstract dispense(machine: VendingMachine): void;
+}

state-pattern/WorkingState.ts

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+import { VendingMachine } from "./VendingMachine";
+import { VendingState } from "./VendingState";
+
+
+export class WorkingState extends VendingState {
+  public insertCoin(machine: VendingMachine): VendingState {
+    console.log('Coin already inserted, cannot insert another');
+    return this;
+  }
+  public dispense(machine: VendingMachine): void {
+    console.log('Dispensing item, transitioning to IdleState');
+  }
+}

state-pattern/main.ts

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+import { IdleState } from "./IdleState";
+import { VendingMachine } from "./VendingMachine";
+import { WorkingState } from "./WorkingState";
+
+
+class StatePattern {
+  static main(): void {
+    console.log('State Pattern');
+    const vendingMachine = new VendingMachine(new IdleState());
+    const vendingMachine2 = new VendingMachine(new WorkingState());
+    const vendingState1 = vendingMachine.insertCoin();
+    const vendingState2 = vendingMachine2.insertCoin();
+    vendingMachine.dispense();
+    vendingMachine2.dispense();
+  }
+}
+
+StatePattern.main();