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
- Add 5s timeout to async tests
- Reduce setTimeout delays in error-handling exercise for faster tests
- Fix makeRequest to return value, not just log
- Fix error-handling test to verify errors don't propagate (correct behavior)

Author: kentcdodds

exercises/01.promises/01.problem.creation/index.ts

@@ -14,7 +14,5 @@ type User = {
 // 🐨 Call fetchUser and log the result when it resolves
 // 💰 fetchUser().then((user) => console.log(user))
 
-// 🐨 When you're done, uncomment this:
-// fetchUser().then((user) => {
-// 	console.log('Results:', JSON.stringify(user))
-// })
+// 🐨 Export your function so we can verify your work
+// 💰 export { fetchUser }

exercises/01.promises/01.problem.creation/package.json

@@ -2,7 +2,7 @@
   "name": "exercises_01.promises_01.problem.creation",
   "type": "module",
   "scripts": {
-    "start": "node index.ts",
+    "start": "npx @kentcdodds/log-module@latest ./index.ts",
     "test": "node --test index.test.ts"
   }
 }

exercises/01.promises/01.solution.creation/index.test.ts

@@ -1,44 +1,52 @@
 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 = JSON.parse(jsonLine.replace('Results:', '').trim())
-
-await test('fetchUser returns a Promise that resolves to a User object', async () => {
-	type User = {
-		id: string
-		name: string
-		email: string
-	}
-
-	assert.ok(
-		'id' in user,
-		'🚨 user should have an id property - check your Promise resolve value',
-	)
-	assert.ok(
-		'name' in user,
-		'🚨 user should have a name property - check your Promise resolve value',
-	)
+await test('fetchUser is exported', () => {
 	assert.ok(
-		'email' in user,
-		'🚨 user should have an email property - check your Promise resolve value',
-	)
-	assert.strictEqual(
-		user.id,
-		'1',
-		'🚨 user.id should be "1" - check your Promise resolve value',
-	)
-	assert.strictEqual(
-		user.name,
-		'Alice',
-		'🚨 user.name should be "Alice" - check your Promise resolve value',
-	)
-	assert.strictEqual(
-		user.email,
-		'[email protected]',
-		'🚨 user.email should be "[email protected]" - check your Promise resolve value',
+		'fetchUser' in solution,
+		'🚨 Make sure you export "fetchUser" - add: export { fetchUser }',
 	)
 })
+
+await test(
+	'fetchUser returns a Promise that resolves to a User object',
+	{ timeout: 5000 },
+	async () => {
+		type User = {
+			id: string
+			name: string
+			email: string
+		}
+
+		const user = await solution.fetchUser()
+
+		assert.ok(
+			'id' in user,
+			'🚨 user should have an id property - check your Promise resolve value',
+		)
+		assert.ok(
+			'name' in user,
+			'🚨 user should have a name property - check your Promise resolve value',
+		)
+		assert.ok(
+			'email' in user,
+			'🚨 user should have an email property - check your Promise resolve value',
+		)
+		assert.strictEqual(
+			user.id,
+			'1',
+			'🚨 user.id should be "1" - check your Promise resolve value',
+		)
+		assert.strictEqual(
+			user.name,
+			'Alice',
+			'🚨 user.name should be "Alice" - check your Promise resolve value',
+		)
+		assert.strictEqual(
+			user.email,
+			'[email protected]',
+			'🚨 user.email should be "[email protected]" - check your Promise resolve value',
+		)
+	},
+)

exercises/01.promises/01.solution.creation/index.ts

@@ -14,11 +14,8 @@ function fetchUser(): Promise<User> {
 				name: 'Alice',
 				email: '[email protected]',
 			})
-		}, 1000)
+		}, 10)
 	})
 }
 
-void fetchUser().then((user) => {
-	console.log('User fetched:', user)
-	console.log('Results:', JSON.stringify(user))
-})
+export { fetchUser }

exercises/01.promises/01.solution.creation/package.json

@@ -2,7 +2,7 @@
   "name": "exercises_01.promises_01.solution.creation",
   "type": "module",
   "scripts": {
-    "start": "node index.ts",
+    "start": "npx @kentcdodds/log-module@latest ./index.ts",
     "test": "node --test index.test.ts"
   }
 }

exercises/01.promises/02.problem.chaining/index.ts

@@ -48,16 +48,5 @@ function fetchOrders(userId: string): Promise<Order[]> {
 // 🐨 Add error handling with .catch()
 // 💰 .catch((error) => console.error('Error:', error))
 
-// 🐨 When you're done, uncomment this:
-// fetchUser()
-// 	.then((user) => fetchOrders(user.id).then((orders) => ({ user, orders })))
-// 	.then(({ user, orders }) => {
-// 		console.log(
-// 			'Results:',
-// 			JSON.stringify({
-// 				user,
-// 				orders,
-// 			}),
-// 		)
-// 	})
-// 	.catch((error) => console.error('Error:', error))
+// 🐨 Export your functions so we can verify your work
+// 💰 export { fetchUser, fetchOrders }

exercises/01.promises/02.problem.chaining/package.json

@@ -2,7 +2,7 @@
   "name": "exercises_01.promises_02.problem.chaining",
   "type": "module",
   "scripts": {
-    "start": "node index.ts",
+    "start": "npx @kentcdodds/log-module@latest ./index.ts",
     "test": "node --test index.test.ts"
   }
 }

exercises/01.promises/02.solution.chaining/index.test.ts

@@ -1,76 +1,97 @@
 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, orders } = JSON.parse(jsonLine.replace('Results:', '').trim())
-
-await test('fetchUser resolves to a User object', async () => {
-	assert.ok(
-		'id' in user,
-		'🚨 user should have an id property - make sure fetchUser resolves correctly',
-	)
+await test('fetchUser and fetchOrders are exported', () => {
 	assert.ok(
-		'name' in user,
-		'🚨 user should have a name property - make sure fetchUser resolves correctly',
+		'fetchUser' in solution,
+		'🚨 Make sure you export "fetchUser" - add: export { fetchUser, fetchOrders }',
 	)
 	assert.ok(
-		'email' in user,
-		'🚨 user should have an email property - make sure fetchUser resolves correctly',
-	)
-	assert.strictEqual(
-		user.id,
-		'1',
-		'🚨 user.id should be "1" - check your Promise resolve value',
-	)
-	assert.strictEqual(
-		user.name,
-		'Alice',
-		'🚨 user.name should be "Alice" - check your Promise resolve value',
-	)
-	assert.strictEqual(
-		user.email,
-		'[email protected]',
-		'🚨 user.email should be "[email protected]" - check your Promise resolve value',
+		'fetchOrders' in solution,
+		'🚨 Make sure you export "fetchOrders" - add: export { fetchUser, fetchOrders }',
 	)
 })
 
-await test('fetchOrders resolves to an array of Order objects', async () => {
-	assert.strictEqual(
-		Array.isArray(orders),
-		true,
-		'🚨 orders should be an array - make sure fetchOrders returns an array',
-	)
-	assert.ok(
-		orders.length > 0,
-		'🚨 orders should have at least one item - check your Promise resolve value',
-	)
-	assert.ok(
-		'id' in orders[0],
-		'🚨 orders[0] should have an id property - check your Promise resolve value',
-	)
-	assert.ok(
-		'userId' in orders[0],
-		'🚨 orders[0] should have a userId property - check your Promise resolve value',
-	)
-	assert.ok(
-		'items' in orders[0],
-		'🚨 orders[0] should have an items property - check your Promise resolve value',
-	)
-	assert.ok(
-		'total' in orders[0],
-		'🚨 orders[0] should have a total property - check your Promise resolve value',
-	)
-	assert.strictEqual(
-		orders[0].userId,
-		'1',
-		'🚨 orders[0].userId should be "1" - make sure you use the userId parameter',
-	)
-})
+await test(
+	'fetchUser resolves to a User object',
+	{ timeout: 5000 },
+	async () => {
+		const user = await solution.fetchUser()
+
+		assert.ok(
+			'id' in user,
+			'🚨 user should have an id property - make sure fetchUser resolves correctly',
+		)
+		assert.ok(
+			'name' in user,
+			'🚨 user should have a name property - make sure fetchUser resolves correctly',
+		)
+		assert.ok(
+			'email' in user,
+			'🚨 user should have an email property - make sure fetchUser resolves correctly',
+		)
+		assert.strictEqual(
+			user.id,
+			'1',
+			'🚨 user.id should be "1" - check your Promise resolve value',
+		)
+		assert.strictEqual(
+			user.name,
+			'Alice',
+			'🚨 user.name should be "Alice" - check your Promise resolve value',
+		)
+		assert.strictEqual(
+			user.email,
+			'[email protected]',
+			'🚨 user.email should be "[email protected]" - check your Promise resolve value',
+		)
+	},
+)
+
+await test(
+	'fetchOrders resolves to an array of Order objects',
+	{ timeout: 5000 },
+	async () => {
+		const orders = await solution.fetchOrders('1')
+
+		assert.strictEqual(
+			Array.isArray(orders),
+			true,
+			'🚨 orders should be an array - make sure fetchOrders returns an array',
+		)
+		assert.ok(
+			orders.length > 0,
+			'🚨 orders should have at least one item - check your Promise resolve value',
+		)
+		assert.ok(
+			'id' in orders[0],
+			'🚨 orders[0] should have an id property - check your Promise resolve value',
+		)
+		assert.ok(
+			'userId' in orders[0],
+			'🚨 orders[0] should have a userId property - check your Promise resolve value',
+		)
+		assert.ok(
+			'items' in orders[0],
+			'🚨 orders[0] should have an items property - check your Promise resolve value',
+		)
+		assert.ok(
+			'total' in orders[0],
+			'🚨 orders[0] should have a total property - check your Promise resolve value',
+		)
+		assert.strictEqual(
+			orders[0].userId,
+			'1',
+			'🚨 orders[0].userId should be "1" - make sure you use the userId parameter',
+		)
+	},
+)
+
+await test('promise chaining works correctly', { timeout: 5000 }, async () => {
+	const user = await solution.fetchUser()
+	const orders = await solution.fetchOrders(user.id)
 
-await test('promise chaining works correctly', async () => {
 	assert.strictEqual(
 		user.id,
 		'1',

exercises/01.promises/02.solution.chaining/index.ts

@@ -21,7 +21,7 @@ function fetchUser(): Promise<User> {
 				name: 'Alice',
 				email: '[email protected]',
 			})
-		}, 1000)
+		}, 10)
 	})
 }
 
@@ -36,25 +36,8 @@ function fetchOrders(userId: string): Promise<Array<Order>> {
 					total: 1299.99,
 				},
 			])
-		}, 500)
+		}, 10)
 	})
 }
 
-fetchUser()
-	.then((user) => {
-		console.log('User:', user)
-		return fetchOrders(user.id)
-	})
-	.then((orders) => {
-		console.log('Orders:', orders)
-		console.log(
-			'Results:',
-			JSON.stringify({
-				user: { id: '1', name: 'Alice', email: '[email protected]' },
-				orders,
-			}),
-		)
-	})
-	.catch((error) => {
-		console.error('Error:', error)
-	})
+export { fetchUser, fetchOrders }

exercises/01.promises/02.solution.chaining/package.json

@@ -2,7 +2,7 @@
   "name": "exercises_01.promises_02.solution.chaining",
   "type": "module",
   "scripts": {
-    "start": "node index.ts",
+    "start": "npx @kentcdodds/log-module@latest ./index.ts",
     "test": "node --test index.test.ts"
   }
 }