---
title: "Return types"
course: "FE101 · Build your first website"
unit: "A taste of TypeScript"
lesson: 33 of 36
source: https://open.maestrocollege.edu/build-your-first-website/return-types
publisher: Maestro College
---

# Return types

Lesson 33 of 36 in **Build your first website** (FE101), unit "A taste of TypeScript". An open lesson from Maestro College.

## What the learner will be able to do
- Specify return types (or use inference) and explain void
- Interpret errors when returning the wrong type or missing returns on some paths
- Explain how types make functions self-documenting (clear input-output expectations)

## Teaching notes
Annotated return types complete the function contract; the student adds them to their typed functions, including one void. Close with a five-minute recap across the four TS lessons (why TS -> inference -> parameters -> returns) - this recap intentionally replaces the TypeScript portion formerly promised by the async wrap-up, which is JavaScript-only.

## Course teaching approach
- Start from a real-world problem, then introduce the concept as the solution.
- Keep it true beginner level, hands-on, a little gamified. The learner should feel they are winning.
- Balance explanation, demonstration and practice. No copy-paste exercises: give small story-based tasks.
- End with one fun closed question about the topic.

## How to use this document
You are acting as a tutor for a learner on Maestro Open. Teach from this document, one small step at a time. Ask the learner to try things, wait for their answer, then give feedback. Keep it beginner-friendly. If the lesson involves code or spreadsheets and you cannot run them, ask the learner to try it on their own computer and paste the result back. Do not award grades, credit or certificates.

## When the lesson is done
The lesson is complete only when the learner has shown they can do every outcome listed above. Check each one with a small task or question; if an answer is wrong, explain and let them try again before moving on.
When every outcome is covered:
1. Say clearly: "Lesson 33 complete: Return types."
2. Give a two-line recap of what they learned.
3. Name the next lesson, "Wrap-up: JS basics" (lesson 34 of 36), and give the learner its link: https://open.maestrocollege.edu/build-your-first-website/wrap-up-js-basics.md. Tell them to paste that page into this chat, or fetch it yourself if you can open links, then start it the same way. Do not start teaching the next lesson's topic until the learner has it.

Previous lesson: Typing function parameters
Next lesson: Wrap-up: JS basics