feat: add new function exercises and enhance documentation

- Introduced new exercises on function declarations, parameters, and returns, including solutions and tests.
- Updated README files to provide clearer instructions and learning objectives.
- Added JSDoc comments to enhance code clarity and IDE support for functions.
- Removed outdated exercises and corresponding files to streamline the learning path.
- Updated package-lock.json to reflect changes in dependencies.

Author: kentcdodds

exercises/05.functions/01.problem.function-declaration/README.mdx

@@ -0,0 +1,11 @@
+// Function Declarations
+// A named function that returns a value
+
+// 🐨 Create a function named `getMessage` that returns "Hello, functions!"
+// Make sure to add an explicit return type of string.
+
+// ✅ Test your function
+// console.log(getMessage()) // "Hello, functions!"
+
+// 🐨 Export your function so we can verify your work
+// export { getMessage }

exercises/05.functions/01.problem.function-declaration/index.ts

@@ -0,0 +1,10 @@
+{
+  "name": "exercises_05.functions_01.problem.function-declaration",
+  "type": "module",
+  "scripts": {
+    "start": "npx @kentcdodds/log-module ./index.ts",
+    "start:watch": "npx @kentcdodds/log-module --watch ./index.ts",
+    "test": "node --test index.test.ts",
+    "test:watch": "node --watch --test index.test.ts"
+  }
+}

exercises/05.functions/01.problem.function-declaration/package.json

@@ -0,0 +1,18 @@
+import assert from 'node:assert/strict'
+import { test } from 'node:test'
+import * as solution from './index.ts'
+
+await test('getMessage is exported', () => {
+	assert.ok(
+		'getMessage' in solution,
+		'🚨 Make sure you export "getMessage" - add: export { getMessage }',
+	)
+})
+
+await test('getMessage returns the expected message', () => {
+	assert.strictEqual(
+		solution.getMessage(),
+		'Hello, functions!',
+		'🚨 getMessage() should return "Hello, functions!"',
+	)
+})

exercises/05.functions/01.solution.function-declaration/README.mdx

@@ -0,0 +1,11 @@
+// Function Declarations
+// A named function that returns a value
+
+function getMessage(): string {
+	return 'Hello, functions!'
+}
+
+// ✅ Test your function
+console.log(getMessage()) // "Hello, functions!"
+
+export { getMessage }

exercises/05.functions/01.solution.function-declaration/index.test.ts

@@ -0,0 +1,10 @@
+{
+  "name": "exercises_05.functions_01.solution.function-declaration",
+  "type": "module",
+  "scripts": {
+    "start": "npx @kentcdodds/log-module ./index.ts",
+    "start:watch": "npx @kentcdodds/log-module --watch ./index.ts",
+    "test": "node --test index.test.ts",
+    "test:watch": "node --watch --test index.test.ts"
+  }
+}

exercises/05.functions/01.solution.function-declaration/index.ts

@@ -1,5 +1,5 @@
 // E-commerce Utility Functions
-// Creating functions with typed parameters and returns
+// Creating functions with typed parameters and return values
 
 // 🐨 Create a function `calculateTax` that:
 // - Takes `amount` (number) and `rate` (number)

exercises/05.functions/01.solution.function-declaration/package.json

@@ -1,5 +1,5 @@
 {
-  "name": "exercises_05.functions_01.problem.parameters-and-returns",
+  "name": "exercises_05.functions_02.problem.parameters-and-returns",
   "type": "module",
   "scripts": {
     "start": "npx @kentcdodds/log-module ./index.ts",