Beginner
TypeScript
Learn TypeScript end to end. Types, interfaces, generics, classes, modules, utility and mapped types, declaration files, and the compiler.
18 lessons7.7h hands-on11 languages
Start learning freeTypeScript course18 lessons, in order
- 120 min
Hello, TypeScript
What TypeScript isTsc compile stepRunning a .ts fileThe play button - 225 min
Type Basics
Primitive typesStringNumberBooleanNullUndefined+3 - 325 min
Arrays and Tuples
Array typesReadonly arraysTuple typesFixed-length tuplesNamed tuple elements - 425 min
Object Types and Interfaces
Object literal typesInterface keywordRequired vs optional propertiesStructural typingExcess property checks - 525 min
Functions
Parameter typesReturn typesVoid returnDefault parametersRest parametersFunction type expressions+1 - 625 min
Union and Literal Types
Union typesString literal typesNumeric literal typesLiteral narrowing with as constUnion of object shapes - 730 min
Type Narrowing
Typeof narrowingTruthiness narrowingEquality narrowingIn operator narrowingInstanceof narrowingDiscriminated unions+1 - 820 min
Type Aliases vs Interfaces
Type aliasesInterface declarationsExtending interfacesIntersection typesDeclaration mergingWhen to pick which - 925 min
Optional, Readonly, and Nullable
Optional propertiesReadonly propertiesNon-null assertion operatorOptional chainingNullish coalescingStrictNullChecks - 1020 min
Enums
Numeric enumsString enumsConst enumsEnums vs string literal unionsReverse mapping caveats - 1130 min
Generics
Generic functionsGeneric interfacesType parametersType inference for genericsBounded generics with extendsDefault type parameters - 1225 min
Classes
Class declarationsConstructorsInstance propertiesAccess modifiers (public, private, protected)Readonly fieldsParameter properties+1 - 1325 min
Inheritance and Abstract Classes
Extends keywordSuper callsMethod overrideAbstract classesAbstract methodsImplements with interface - 1425 min
Modules
ES module syntaxNamed exportsDefault exportType-only importsRe-exportsModule resolution basics - 1530 min
Utility Types
Partial<T>Required<T>Readonly<T>Pick<T, K>Omit<T, K>Record<K, V>+2 - 1630 min
Mapped and Conditional Types
Keyof operatorMapped types syntaxKey remapping with asConditional typesInfer keywordDistributive conditional types - 1725 min
Declaration Files and Libraries
.d.ts filesDefinitelyTyped (@types packages)Ambient declarationsDeclare moduleTypeRoots and types option - 1830 min
tsconfig and the Compiler
Tsconfig.jsonStrict modeTarget and libModule and moduleResolutionOutDir and rootDirIncremental and watch+1
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