refactor: switch to export-based evaluation pattern

- Replace console.log Results output with direct exports
- Rewrite tests to import modules directly instead of parsing stdout
- Add export instructions with 🐨 and 💰 hints in problem files
- Add helpful 🚨 error messages for common mistakes
- Fix interface export issue (interfaces are type-only, not runtime values)

Author: kentcdodds

exercises/01.classes/01.problem.class-basics/index.ts

@@ -19,25 +19,5 @@
 // cart.addItem(mouse)
 // console.log(cart.getTotal())
 
-// 🐨 When you're done, uncomment this:
-// const sampleCart = new ShoppingCart()
-// const sampleLaptop = new Product('Laptop', 999.99)
-// const sampleMouse = new Product('Mouse', 29.99)
-// sampleCart.addItem(sampleLaptop)
-// sampleCart.addItem(sampleMouse)
-// console.log(
-// 	'Results:',
-// 	JSON.stringify({
-// 		product: {
-// 			name: sampleLaptop.name,
-// 			price: sampleLaptop.price,
-// 			description: sampleLaptop.getDescription(),
-// 		},
-// 		cart: {
-// 			itemsCount: sampleCart.items.length,
-// 			firstItemName: sampleCart.items[0]?.name,
-// 			secondItemName: sampleCart.items[1]?.name,
-// 			total: sampleCart.getTotal(),
-// 		},
-// 	}),
-// )
+// 🐨 Export your classes so we can verify your work
+// 💰 export { Product, ShoppingCart }

exercises/01.classes/01.problem.class-basics/package.json

@@ -2,7 +2,7 @@
   "name": "exercises_01.classes_01.problem.class-basics",
   "type": "module",
   "scripts": {
-    "start": "node index.ts",
+    "start": "npx @kentcdodds/log-module@latest ./index.ts",
     "test": "node --test index.test.ts"
   }
 }

exercises/01.classes/01.solution.class-basics/index.test.ts

@@ -1,70 +1,93 @@
 import assert from 'node:assert/strict'
-import { execSync } from 'node:child_process'
 import { test } from 'node:test'
+import * as solution from './index.ts'
 
-const output = execSync('npm start --silent', { encoding: 'utf8' })
-const jsonLine = output.split('\n').find((line) => line.startsWith('Results:'))
-assert.ok(jsonLine, '🚨 Missing "Results:" output line')
-const { product, cart, emptyCart } = JSON.parse(
-	jsonLine.replace('Results:', '').trim(),
-)
+await test('Product class should be exported', () => {
+	assert.ok(
+		'Product' in solution,
+		'🚨 Make sure you export "Product" - add: export { Product, ShoppingCart }',
+	)
+})
+
+await test('ShoppingCart class should be exported', () => {
+	assert.ok(
+		'ShoppingCart' in solution,
+		'🚨 Make sure you export "ShoppingCart" - add: export { Product, ShoppingCart }',
+	)
+})
 
 await test('Product class should create instances with name and price', () => {
+	const sampleLaptop = new solution.Product('Laptop', 999.99)
 	assert.strictEqual(
-		product.name,
+		sampleLaptop.name,
 		'Laptop',
 		'🚨 Product.name should be "Laptop" - check your class property definition',
 	)
 	assert.strictEqual(
-		product.price,
+		sampleLaptop.price,
 		999.99,
 		'🚨 Product.price should be 999.99 - check your class property definition',
 	)
 })
 
 await test('Product getDescription should return formatted string', () => {
+	const sampleLaptop = new solution.Product('Laptop', 999.99)
 	assert.strictEqual(
-		product.description,
+		sampleLaptop.getDescription(),
 		'Product: Laptop - $999.99',
-		'🚨 getDescription() should return "Product: Mouse - $29.99" - check your method implementation and formatting',
+		'🚨 getDescription() should return "Product: Laptop - $999.99" - check your method implementation and formatting',
 	)
 })
 
 await test('ShoppingCart should initialize with empty items array', () => {
+	const emptyCart = new solution.ShoppingCart()
 	assert.strictEqual(
-		emptyCart.itemsCount,
+		emptyCart.items.length,
 		0,
 		'🚨 ShoppingCart.items.length should be 0 - check your class property initialization',
 	)
 })
 
 await test('ShoppingCart addItem should add products to cart', () => {
+	const sampleCart = new solution.ShoppingCart()
+	const sampleLaptop = new solution.Product('Laptop', 999.99)
+	const sampleMouse = new solution.Product('Mouse', 29.99)
+	sampleCart.addItem(sampleLaptop)
+	const afterFirstAddCount = sampleCart.items.length
+	sampleCart.addItem(sampleMouse)
+
 	assert.strictEqual(
-		cart.itemsAfterFirstAdd,
+		afterFirstAddCount,
 		1,
 		'🚨 After adding one item, items.length should be 1 - check your addItem method implementation',
 	)
 	assert.strictEqual(
-		cart.firstItemName,
+		sampleCart.items[0]?.name,
 		'Laptop',
 		'🚨 items[0] should be the laptop product - check your addItem method implementation',
 	)
 
 	assert.strictEqual(
-		cart.itemsCount,
+		sampleCart.items.length,
 		2,
 		'🚨 After adding two items, items.length should be 2 - check your addItem method implementation',
 	)
 	assert.strictEqual(
-		cart.secondItemName,
+		sampleCart.items[1]?.name,
 		'Mouse',
 		'🚨 items[1] should be the mouse product - check your addItem method implementation',
 	)
 })
 
 await test('ShoppingCart getTotal should calculate sum of all item prices', () => {
+	const sampleCart = new solution.ShoppingCart()
+	const sampleLaptop = new solution.Product('Laptop', 999.99)
+	const sampleMouse = new solution.Product('Mouse', 29.99)
+	sampleCart.addItem(sampleLaptop)
+	sampleCart.addItem(sampleMouse)
+
 	assert.strictEqual(
-		cart.total,
+		sampleCart.getTotal(),
 		1029.98,
 		'🚨 getTotal() should return 1029.98 (sum of 999.99 + 29.99) - check your method implementation and price calculation',
 	)

exercises/01.classes/01.solution.class-basics/index.ts

@@ -41,31 +41,4 @@ cart.addItem(laptop)
 cart.addItem(mouse)
 console.log(`Cart total: $${cart.getTotal()}`)
 
-const sampleCart = new ShoppingCart()
-const emptyCart = new ShoppingCart()
-const sampleLaptop = new Product('Laptop', 999.99)
-const sampleMouse = new Product('Mouse', 29.99)
-sampleCart.addItem(sampleLaptop)
-const afterFirstAddCount = sampleCart.items.length
-sampleCart.addItem(sampleMouse)
-
-console.log(
-	'Results:',
-	JSON.stringify({
-		product: {
-			name: sampleLaptop.name,
-			price: sampleLaptop.price,
-			description: sampleLaptop.getDescription(),
-		},
-		cart: {
-			itemsCount: sampleCart.items.length,
-			itemsAfterFirstAdd: afterFirstAddCount,
-			firstItemName: sampleCart.items[0]?.name,
-			secondItemName: sampleCart.items[1]?.name,
-			total: sampleCart.getTotal(),
-		},
-		emptyCart: {
-			itemsCount: emptyCart.items.length,
-		},
-	}),
-)
+export { Product, ShoppingCart }

exercises/01.classes/01.solution.class-basics/package.json

@@ -2,7 +2,7 @@
   "name": "exercises_01.classes_01.solution.class-basics",
   "type": "module",
   "scripts": {
-    "start": "node index.ts",
+    "start": "npx @kentcdodds/log-module@latest ./index.ts",
     "test": "node --test index.test.ts"
   }
 }

exercises/01.classes/02.problem.constructors/index.ts

@@ -26,26 +26,5 @@
 // const config = new Config()
 // const customConfig = new Config('example.com', 8080, true)
 
-// 🐨 When you're done, uncomment this:
-// const sampleAccount = new BankAccount('12345')
-// sampleAccount.deposit(100)
-// sampleAccount.deposit(50)
-// console.log(
-// 	'Results:',
-// 	JSON.stringify({
-// 		user: { name: user.name, email: user.email, role: user.role },
-// 		admin: { name: admin.name, email: admin.email, role: admin.role },
-// 		account: {
-// 			accountNumber: sampleAccount.accountNumber,
-// 			initialBalance: 0,
-// 			balanceAfterFirstDeposit: 100,
-// 			balanceAfterSecondDeposit: 150,
-// 		},
-// 		config: { host: config.host, port: config.port, debug: config.debug },
-// 		customConfig: {
-// 			host: customConfig.host,
-// 			port: customConfig.port,
-// 			debug: customConfig.debug,
-// 		},
-// 	}),
-// )
+// 🐨 Export your classes so we can verify your work
+// 💰 export { User, BankAccount, Config }

exercises/01.classes/02.problem.constructors/package.json

@@ -2,7 +2,7 @@
   "name": "exercises_01.classes_02.problem.constructors",
   "type": "module",
   "scripts": {
-    "start": "node index.ts",
-    "test": "node --experimental-transform-types --test index.test.ts"
+    "start": "npx @kentcdodds/log-module@latest ./index.ts",
+    "test": "node --test index.test.ts"
   }
 }

exercises/01.classes/02.solution.constructors/index.test.ts

@@ -1,15 +1,30 @@
 import assert from 'node:assert/strict'
-import { execSync } from 'node:child_process'
 import { test } from 'node:test'
+import * as solution from './index.ts'
 
-const output = execSync('npm start --silent', { encoding: 'utf8' })
-const jsonLine = output.split('\n').find((line) => line.startsWith('Results:'))
-assert.ok(jsonLine, '🚨 Missing "Results:" output line')
-const { user, admin, account, config, customConfig } = JSON.parse(
-	jsonLine.replace('Results:', '').trim(),
-)
+await test('User class should be exported', () => {
+	assert.ok(
+		'User' in solution,
+		'🚨 Make sure you export "User" - add: export { User, BankAccount, Config }',
+	)
+})
+
+await test('BankAccount class should be exported', () => {
+	assert.ok(
+		'BankAccount' in solution,
+		'🚨 Make sure you export "BankAccount" - add: export { User, BankAccount, Config }',
+	)
+})
+
+await test('Config class should be exported', () => {
+	assert.ok(
+		'Config' in solution,
+		'🚨 Make sure you export "Config" - add: export { User, BankAccount, Config }',
+	)
+})
 
 await test('User constructor should set name, email, and default role', () => {
+	const user = new solution.User('Alice', '[email protected]')
 	assert.strictEqual(
 		user.name,
 		'Alice',
@@ -28,6 +43,7 @@ await test('User constructor should set name, email, and default role', () => {
 })
 
 await test('User constructor should accept custom role', () => {
+	const admin = new solution.User('Bob', '[email protected]', 'admin')
 	assert.strictEqual(
 		admin.name,
 		'Bob',
@@ -46,32 +62,39 @@ await test('User constructor should accept custom role', () => {
 })
 
 await test('BankAccount constructor should set accountNumber and default balance', () => {
+	const sampleAccount = new solution.BankAccount('12345')
 	assert.strictEqual(
-		account.accountNumber,
+		sampleAccount.accountNumber,
 		'12345',
 		'🚨 BankAccount.accountNumber should be "12345" - check your constructor parameter assignment',
 	)
 	assert.strictEqual(
-		account.initialBalance,
+		sampleAccount.getBalance(),
 		0,
 		'🚨 BankAccount.getBalance() should return 0 initially - check your constructor initialization',
 	)
 })
 
 await test('BankAccount deposit should increase balance', () => {
+	const sampleAccount = new solution.BankAccount('12345')
+	sampleAccount.deposit(100)
+	const balanceAfterFirstDeposit = sampleAccount.getBalance()
+	sampleAccount.deposit(50)
+
 	assert.strictEqual(
-		account.balanceAfterFirstDeposit,
+		balanceAfterFirstDeposit,
 		100,
 		'🚨 After depositing 100, getBalance() should return 100 - check your deposit method implementation',
 	)
 	assert.strictEqual(
-		account.balanceAfterSecondDeposit,
+		sampleAccount.getBalance(),
 		150,
 		'🚨 After depositing another 50, getBalance() should return 150 - check your deposit method accumulates correctly',
 	)
 })
 
 await test('Config constructor should use default values', () => {
+	const config = new solution.Config()
 	assert.strictEqual(
 		config.host,
 		'localhost',
@@ -90,6 +113,7 @@ await test('Config constructor should use default values', () => {
 })
 
 await test('Config constructor should accept custom values', () => {
+	const customConfig = new solution.Config('example.com', 8080, true)
 	assert.strictEqual(
 		customConfig.host,
 		'example.com',

exercises/01.classes/02.solution.constructors/index.ts

@@ -60,27 +60,4 @@ const customConfig = new Config('example.com', 8080, true)
 console.log(`Default config: ${config.host}:${config.port}`)
 console.log(`Custom config: ${customConfig.host}:${customConfig.port}`)
 
-const sampleAccount = new BankAccount('12345')
-sampleAccount.deposit(100)
-const balanceAfterFirstDeposit = sampleAccount.getBalance()
-sampleAccount.deposit(50)
-
-console.log(
-	'Results:',
-	JSON.stringify({
-		user: { name: user.name, email: user.email, role: user.role },
-		admin: { name: admin.name, email: admin.email, role: admin.role },
-		account: {
-			accountNumber: sampleAccount.accountNumber,
-			initialBalance: 0,
-			balanceAfterFirstDeposit,
-			balanceAfterSecondDeposit: sampleAccount.getBalance(),
-		},
-		config: { host: config.host, port: config.port, debug: config.debug },
-		customConfig: {
-			host: customConfig.host,
-			port: customConfig.port,
-			debug: customConfig.debug,
-		},
-	}),
-)
+export { User, BankAccount, Config }

exercises/01.classes/02.solution.constructors/package.json

@@ -2,7 +2,7 @@
   "name": "exercises_01.classes_02.solution.constructors",
   "type": "module",
   "scripts": {
-    "start": "node index.ts",
-    "test": "node --experimental-transform-types --test index.test.ts"
+    "start": "npx @kentcdodds/log-module@latest ./index.ts",
+    "test": "node --test index.test.ts"
   }
 }