Skip to main content

The Type System

Learning TypeScript's The Type System chapter covers how TypeScript's type system works at its core:

  • What a "type" is and the primitive types recognized by TypeScript
  • What a "type system" is and how TypeScript's type system understands code
  • How type errors compare to syntax errors
  • Inferred variable types and variable assignability
  • Type annotations to explicitly declare variable types and avoid evolving any types
  • Object member checking on type shapes
  • ECMAScript module files' declaration scoping compared to script files