Skip to content
skillbld
All courses

Learn TypeScript, the typed version of JavaScript used by most large web projects. Each day explains one idea with diagrams, real TypeScript you can edit and type-check in your browser, and a quick knowledge check.

  • 14 days
  • ~30 min / day
  • Intermediate
  • Free account required
0/14

Ready when you are

Saved on this device. No account needed.

Start Day 1

The big picture

Everything you'll cover, and how it fits together.

Mind map · click a dot to fold, drag to pan

Day by day

Go at your own pace. Your progress is remembered on this device.

  1. 1
    Day 1Up next 30 min

    Why TypeScript?

    What TypeScript adds to JavaScript, and your first type errors.

    Static typesCompilingType errors
  2. 2
    Day 2 30 min

    Basic Types

    Annotations, inference and the everyday types.

    AnnotationsInferenceany vs unknown
  3. 3
    Day 3Coming soon 30 min

    Functions

    Type parameters, return values and callbacks.

    ParametersReturn typesFunction types
  4. 4
    Day 4Coming soon 30 min

    Objects & Interfaces

    Describe the shape of your data.

    Object typesinterfaceOptional & readonly
  5. 5
    Day 5Coming soon 30 min

    Union Types

    Values that can be one of several types.

    UnionsLiteral typesDiscriminated unions
  6. 6
    Day 6Coming soon 30 min

    Narrowing

    Help TypeScript work out the exact type.

    typeof & inType guardsnever
  7. 7
    Day 7Coming soon 30 min

    Arrays, Tuples & Enums

    Collections and fixed sets of values.

    Tuplesreadonlyas const
  8. 8
    Day 8Coming soon 30 min

    Generics

    Write code that works with any type, safely.

    Generic functionsConstraintsGeneric types
  9. 9
    Day 9Coming soon 30 min

    Classes

    Typed classes, access modifiers and interfaces.

    public / privateimplementsabstract
  10. 10
    Day 10Coming soon 30 min

    Utility Types

    Built-in helpers that transform types.

    Partial & RequiredPick & OmitRecord
  11. 11
    Day 11Coming soon 30 min

    Advanced Types

    keyof, mapped and conditional types.

    keyof & typeofMapped typesConditional types
  12. 12
    Day 12Coming soon 30 min

    Modules & Declarations

    Share types across files and use typed libraries.

    import type.d.ts files@types
  13. 13
    Day 13Coming soon 30 min

    Async Code & APIs

    Type promises and data from the outside world.

    Promise<T>Typing API dataRuntime validation
  14. 14
    Day 14Coming soon 30 min

    Projects & Tooling

    tsconfig, strict mode and a small typed project.

    tsconfig.jsonStrict modeMini project