Resolves #3

src/bank.ts

@@ -53,4 +53,17 @@ export default class Bank {
             throw new Error('Account not found');
         }
     }
+
+    withdraw(accountNumber: number, amount: number): void {
+        let account =  this.accounts.find(account => account.accountNumber === accountNumber);
+        if (account) {
+            if (account.balance < amount) {
+                throw new Error('Insufficient balance');
+            }
+            account.balance -= amount;
+        }
+        else {
+            throw new Error('Account not found');
+        }
+    }
 }

tests/bank.test.ts

@@ -62,4 +62,21 @@ describe('Bank class', () => {
             expect(() => bank.deposit(12345, 100)).toThrow('Account not found');
         });
     });
+
+    describe('withdraw', () => {
+        it('should withdraw money from the account', () => {
+            bank.deposit(testAccount.accountNumber!, 100);
+            bank.withdraw(testAccount.accountNumber!, 50);
+            expect(bank.getBalance(testAccount.accountNumber!)).toBe(50);
+        });
+
+        it('should throw an error if withdrawal amount is greater than the balance', () => {
+            bank.deposit(testAccount.accountNumber!, 100);
+            expect(() => bank.withdraw(testAccount.accountNumber!, 150)).toThrow('Insufficient balance');
+        });
+
+        it('should throw an error when withdrawing from an invalid account', () => {
+            expect(() => bank.withdraw(12345, 50)).toThrow('Account not found');
+        });
+    });
 });