Create SG.ts

code/Behavioral Design Patterns/SG.ts

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+// Handler interface
+interface Approver {
+    setNext(nextApprover: Approver): Approver;
+    processRequest(amount: number): void;
+}
+
+// Base Handler class implementing the Approver interface
+abstract class AbstractApprover implements Approver {
+    private nextApprover: Approver | null = null;
+
+    setNext(nextApprover: Approver): Approver {
+        this.nextApprover = nextApprover;
+        return nextApprover;
+    }
+
+    processRequest(amount: number): void {
+        if (this.canApprove(amount)) {
+            this.approve(amount);
+        } else if (this.nextApprover) {
+            this.nextApprover.processRequest(amount);
+        }
+    }
+
+    protected abstract canApprove(amount: number): boolean;
+    protected abstract approve(amount: number): void;
+}
+
+// Concrete Handler 1
+class Manager extends AbstractApprover {
+    protected canApprove(amount: number): boolean {
+        return amount <= 1000;
+    }
+
+    protected approve(amount: number): void {
+        console.log(`Manager approves the purchase of $${amount}.`);
+    }
+}
+
+// Concrete Handler 2
+class Director extends AbstractApprover {
+    protected canApprove(amount: number): boolean {
+        return amount <= 5000;
+    }
+
+    protected approve(amount: number): void {
+        console.log(`Director approves the purchase of $${amount}.`);
+    }
+}
+
+// Concrete Handler 3
+class VicePresident extends AbstractApprover {
+    protected canApprove(amount: number): boolean {
+        return amount <= 10000;
+    }
+
+    protected approve(amount: number): void {
+        console.log(`Vice President approves the purchase of $${amount}.`);
+    }
+}
+
+// Client
+const manager = new Manager();
+const director = new Director();
+const vicePresident = new VicePresident();
+
+// Set up the chain of responsibility
+manager.setNext(director).setNext(vicePresident);
+
+// Test the chain with different purchase amounts
+manager.processRequest(800);   // Manager approves the purchase of $800
+manager.processRequest(4500);  // Director approves the purchase of $4500
+manager.processRequest(10000); // Vice President approves the purchase of $10000
+