fix: add export {} to make files modules and fix typecheck errors

Author: kentcdodds

exercises/03.primitive-types/01.problem.numbers-and-strings/index.ts

@@ -12,13 +12,13 @@
 // 💰 Use backticks ` and ${variable} syntax
 
 // ✅ These console.logs will verify your work
-// @ts-expect-error - 💣 remove this comment
 console.log('Price:', price)
-// @ts-expect-error - 💣 remove this comment
+// @ts-expect-error - 💣 remove this comment once you create the productName variable
 console.log('Product:', productName)
-// @ts-expect-error - 💣 remove this comment
+// @ts-expect-error - 💣 remove this comment once you create the quantity variable
 console.log('Quantity:', quantity)
-// @ts-expect-error - 💣 remove this comment
+// @ts-expect-error - 💣 remove this comment once you create the description variable
 console.log('Description:', description)
 
 // 🦺 This line ensures TypeScript treats this as a module
+export {}

exercises/04.control-flow/02.problem.loops/index.ts

@@ -18,3 +18,6 @@ const prices: Array<number> = [29.99, 9.99, 49.99, 4.99, 19.99]
 
 // console.log(`Total: $${total.toFixed(2)}`)
 // console.log(`Expensive items (>$10): ${expensiveItemCount}`)
+
+// 🦺 This line ensures TypeScript treats this as a module
+export {}

exercises/04.control-flow/03.problem.for-of-iteration/index.ts

@@ -20,3 +20,6 @@ const prices: Array<number> = [29.99, 9.99, 49.99, 4.99, 19.99]
 // console.log(`Total: $${total.toFixed(2)}`)
 // console.log(`Average: $${average.toFixed(2)}`)
 // console.log(`Highest: $${highestPrice.toFixed(2)}`)
+
+// 🦺 This line ensures TypeScript treats this as a module
+export {}