Reference · 17 terms
Glossary
Every short form used across the series. Inside a lesson, hover or tap any dotted term to see the same entry in place.
TypeScript
- branded typeBranded type
- A type with a hidden tag so that, for example, a UserId cannot be used where an OrderId is expected.Lesson 6 →
- conditional typeConditional type
- A type that chooses between two types based on a check, written T extends U ? X : Y.Lesson 4 →
- declaration fileDeclaration file (.d.ts)
- A file that describes the types of JavaScript code without containing the code.Lesson 5 →
- discriminated unionDiscriminated union
- A union of object types that share a literal field, such as kind, which tells them apart.Lesson 1 →
- genericGenerics
- Types and functions that take type parameters, so one definition works for many types.Lesson 3 →
- mapped typeMapped type
- A type made by looping over the keys of another type.Lesson 4 →
- moduleResolutionmoduleResolution
- The setting that decides how the compiler finds the file behind an import.Lesson 5 →
- narrowingNarrowing
- Checks like typeof or in that let TypeScript treat a value as a more specific type inside a block.Lesson 1 →
- satisfiessatisfies
- An operator that checks a value against a type without widening its inferred type.Lesson 2 →
- strict modeStrict mode
- A group of compiler checks (such as strictNullChecks and noImplicitAny) that catch many mistakes.Lesson 0 →
- structural typingStructural typing
- Two types are compatible if their shapes match, even when their names differ.Lesson 2 →
- tsconfigtsconfig.json
- The file that tells the TypeScript compiler which files to read and which checks to turn on.Lesson 0 →
- type erasureType erasure
- TypeScript types are removed when the code is compiled, so they do not exist at run time.Lesson 0 →
- type inferenceType inference
- TypeScript works out a type from the value, so you do not have to write it.Lesson 1 →
- unknownunknown
- A safe version of any: you must check the value before using it.Lesson 1 →
- utility typesUtility types
- Built-in helper types such as Partial, Pick, Omit and Record that build new types from old ones.Lesson 4 →
- ZodZod
- A library that checks data at run time and gives you a matching TypeScript type.Lesson 6 →