fix: use Array<T> syntax consistently in exercises

- Changed array type annotations from `type[]` to `Array<type>` in problem files
- Updated solution files to match
- Added note in never-type exercise explaining generics will be covered later

This ensures consistency between problem hints and solutions, reducing learner confusion.

Author: kentcdodds

exercises/02.variables/02.problem.reassignment-vs-mutation/index.ts

@@ -1,7 +1,7 @@
 // Understanding Reassignment vs Mutation
 
 // This array is declared with const
-const shoppingList: string[] = ['milk', 'eggs', 'bread']
+const shoppingList: Array<string> = ['milk', 'eggs', 'bread']
 
 console.log('Original list:', shoppingList)
 

exercises/03.control-flow/02.problem.loops/index.ts

@@ -1,7 +1,7 @@
 // Shopping Cart Calculator
 // Using loops to process arrays
 
-const prices: number[] = [29.99, 9.99, 49.99, 4.99, 19.99]
+const prices: Array<number> = [29.99, 9.99, 49.99, 4.99, 19.99]
 
 // 🐨 Create a variable `total` starting at 0
 // 💰 let total = 0

exercises/03.control-flow/03.problem.for-of-iteration/index.ts

@@ -1,7 +1,7 @@
 // Shopping Cart Analysis
 // Using for...of for cleaner iteration
 
-const prices: number[] = [29.99, 9.99, 49.99, 4.99, 19.99]
+const prices: Array<number> = [29.99, 9.99, 49.99, 4.99, 19.99]
 
 // 🐨 Create variables for total, count, and highest price
 // let total = 0

exercises/04.functions/04.problem.arrow-functions/index.ts

@@ -12,7 +12,7 @@ function greet(name: string): string {
 }
 
 // 🐨 Convert this to an arrow function (keep the explicit return - it has multiple lines)
-function calculateTotal(prices: number[], taxRate: number): number {
+function calculateTotal(prices: Array<number>, taxRate: number): number {
 	const subtotal = prices.reduce((sum, price) => sum + price, 0)
 	const tax = subtotal * taxRate
 	return subtotal + tax

exercises/04.functions/04.solution.arrow-functions/index.ts

@@ -8,7 +8,7 @@ const double = (n: number) => n * 2
 const greet = (name: string) => `Hello, ${name}!`
 
 // Arrow function with explicit return (multiple lines)
-const calculateTotal = (prices: number[], taxRate: number) => {
+const calculateTotal = (prices: Array<number>, taxRate: number) => {
 	const subtotal = prices.reduce((sum, price) => sum + price, 0)
 	const tax = subtotal * taxRate
 	return subtotal + tax
@@ -18,7 +18,7 @@ const calculateTotal = (prices: number[], taxRate: number) => {
 const isEven = (n: number) => n % 2 === 0
 
 // Function using arrow function callbacks
-function processNumbers(numbers: number[]) {
+function processNumbers(numbers: Array<number>) {
 	return {
 		doubled: numbers.map((n) => n * 2),
 		evens: numbers.filter((n) => n % 2 === 0),

exercises/05.void-and-never/02.problem.never-type/index.ts

@@ -10,6 +10,8 @@
 // 🐨 Create `assertNonNull` that takes a value of type T | null
 // If null, throw an error. Otherwise, return the value.
 // 💰 function assertNonNull<T>(value: T | null, message: string): T
+// 🦉 Note: The <T> syntax is called "generics" - we'll cover this in detail
+// in the Type Safety workshop. For now, just follow the pattern above.
 
 // Example of exhaustiveness checking
 type Status = 'pending' | 'success' | 'error'