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YOUR TYPESCRIPT LEARNING PATH

A little more TypeScript.
A little more confidence.

One idea at a time, with examples you can follow and checkpoints to see what’s clicking. New here? Begin with chapter one. Know a little already? Jump right in.

Before you start

Bring basic JavaScript variables, functions, arrays, and object literals. Classes are taught later; you do not need to finish the whole JavaScript course first.

Review a foundation whenever you need it: JavaScript values · JavaScript arrays · JavaScript functions · JavaScript object literals

Start chapter one Ready for the final?
14 open chapters. Your progress is saved as you go.

Your chapters

Choose any starting point
  1. 01

    Read compiler feedback and run a checked program

    Intermediate

    Use a type error as specific feedback while keeping type checking separate from execution.

    Start here, or skip ahead
    Open chapter: Read compiler feedback and run a checked program
  2. 02

    Types as working contracts

    Beginner

    Describe JavaScript values and function boundaries precisely.

    Open whenever you’re ready
    Open chapter: Types as working contracts
  3. 03

    Object shapes and readonly views

    Beginner

    Model records without confusing optional fields and immutability.

    Open whenever you’re ready
    Open chapter: Object shapes and readonly views
  4. 04

    Tuples, rest parameters, and array boundaries

    Intermediate

    Use positional contracts when each position has a different meaning.

    Open whenever you’re ready
    Open chapter: Tuples, rest parameters, and array boundaries
  5. 05

    Narrowing and explicit states

    Intermediate

    Represent alternatives so invalid combinations are difficult to express.

    Open whenever you’re ready
    Open chapter: Narrowing and explicit states
  6. 06

    Literal inference and checked configuration

    Intermediate

    Retain useful specific types without pretending assertions validate data.

    Open whenever you’re ready
    Open chapter: Literal inference and checked configuration
  7. 07

    Preserve relationships with generics

    Intermediate

    Connect input and output types without discarding information.

    Open whenever you’re ready
    Open chapter: Preserve relationships with generics
  8. 08

    Function compatibility and callback promises

    Advanced

    Make callback types reflect every call the implementation may make.

    Open whenever you’re ready
    Open chapter: Function compatibility and callback promises
  9. 09

    Classes, structural contracts, and private state

    Intermediate

    Keep public behavior separate from runtime representation.

    Open whenever you’re ready
    Open chapter: Classes, structural contracts, and private state
  10. 10

    Module boundaries and type-only dependencies

    Intermediate

    Separate compile-time contracts from runtime code.

    Open whenever you’re ready
    Open chapter: Module boundaries and type-only dependencies
  11. 11

    Typed asynchronous results and explicit failure

    Advanced

    Model failure without confusing it with a missing return value.

    Open whenever you’re ready
    Open chapter: Typed asynchronous results and explicit failure
  12. 12

    Derive API types from one model

    Advanced

    Use mapped types to prevent duplicated contracts from drifting.

    Open whenever you’re ready
    Open chapter: Derive API types from one model
  13. 13

    Conditional types and union distribution

    Advanced

    Reason about type transformations without confusing them with runtime branches.

    Open whenever you’re ready
    Open chapter: Conditional types and union distribution
  14. 14

    Unknown input and trustworthy results

    Advanced

    Connect runtime validation to accurate static contracts.

    Open whenever you’re ready
    Open chapter: Unknown input and trustworthy results

PUT IT TOGETHER

Final assessment & certificate

32 multiple-choice questions and 2 written coding problems. Pass the knowledge section at 80% overall and at least 50% in every chapter area, complete and review the written practice, and meet the attempt-integrity checks to unlock your certificate.

The certificate records a CodeQuest foundations assessment. Written work is self-reviewed; identity and independent proficiency are not verified.

Open final assessment

Take an issuer-recorded assessment with a verifiable certificate

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