TypeScript / Basic

TypeScript โ€” Basic

Understand values, narrowing, functions, objects, and checked sequences.

6 lessons ยท No account required

What you will learn

  • Explain the static and runtime obligations of the levelโ€™s interfaces.
  • Solve worked exercises and reproduce complete examples under the stated compiler settings.

  1. The checker, emitter, and JavaScript runtime

    Separate source checking from JavaScript execution, pin a reproducible compiler baseline, and identify which assumptions belong to the runtime.

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  2. Values, inference, and control flow

    Use inference to express intent without redundant annotations, then reason about JavaScript values and boundary conditions explicitly.

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  3. Unions, narrowing, and nullability

    Represent alternatives honestly and use runtime observations to justify property access, including explicit handling of missing values.

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  4. Functions, contracts, and callbacks

    Express argument and result relationships, distinguish optional inputs from missing validation, and pass behavior through appropriately typed callbacks.

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  5. Objects, interfaces, and structural types

    Describe object capabilities without confusing a static view with exact runtime shape, ownership, or deep immutability.

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  6. Arrays, tuples, and checked indexing

    Model sequences and fixed positional records, account for absent elements, and distinguish readonly views from independent runtime copies.

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