TypeScript

Question 1

What is TypeScript?

Answer 1

TypeScript is a superset of JavaScript that adds static typing.

Question 2

Static Typing

Answer 2

TypeScript allows you to define variable types, making code more predictable and easier to debug.

Question 3

Transpilation

Answer 3

TypeScript code is compiled into JavaScript for execution in browsers or Node.js.

Question 4

TypeScript File Extension

Answer 4

TypeScript files use the .ts extension.

Question 5

Benefits of TypeScript

Answer 5

Improves code quality, better error detection, supports modern JS features.

Question 6

Interfaces

Answer 6

Used to define contracts for objects, specifying their structure.

Question 7

Classes in TypeScript

Answer 7

Allow for creating objects with defined properties and methods, supporting OOP principles.

Question 8

Enums

Answer 8

Define a set of named constants, making code more readable.

Question 9

Generics

Answer 9

Enable writing reusable and type-safe code components.

Question 10

Union Types

Answer 10

Allow variables to hold more than one type, e.g., string | number.

Question 11

Type Aliases

Answer 11

Provide a way to name and reuse custom types.

Question 12

Literal Types

Answer 12

Restrict a variable to specific values, e.g., let direction: ‘up’ | ‘down’.

Question 13

Type Inference

Answer 13

TypeScript can infer variable types based on assigned values.

Question 14

Any Type

Answer 14

A type that disables type checking, useful in dynamic code.

Question 15

Never Type

Answer 15

Indicates values that never occur, e.g., in unreachable code.

Question 16

Void Type

Answer 16

Used for functions that don’t return a value.

Question 17

Tuple

Answer 17

An array with fixed types and length.

Question 18

Type Assertion

Answer 18

Tell the compiler to treat a value as a specific type using as or <>.

Question 19

Optional Parameters

Answer 19

Functions can define optional parameters with the ? syntax.

Question 20

Readonly Modifier

Answer 20

Prevents reassignment of properties or variables.

Question 21

Access Modifiers

Answer 21

Keywords like public, private, and protected control property access.

Question 22

Default Parameters

Answer 22

Functions can have parameters with default values.

Question 23

Decorators

Answer 23

Special annotations used to modify classes or methods at runtime.

Question 24

Namespaces

Answer 24

Used to organize and group related code.

Question 25

Modules

Answer 25

Allow splitting code into reusable files and importing/exporting between them.

Question 26

TypeScript Compiler

Answer 26

The tsc command compiles TypeScript to JavaScript.

Question 27

Configuration File

Answer 27

tsconfig.json configures TypeScript compiler options.

Question 28

Strict Mode

Answer 28

Enabled in tsconfig.json to enforce strict typing rules.

Question 29

Declaration Files

Answer 29

Files with a .d.ts extension provide type definitions for JavaScript libraries.

Question 30

Mapped Types

Answer 30

Transform properties in a type, e.g., making them optional.

Question 31

Intersection Types

Answer 31

Combine multiple types into one using &.

Question 32

Keyof Operator

Answer 32

Get all keys of a type as a union.

Question 33

Indexed Access Types

Answer 33

Access the type of a property in an object type.

Question 34

Utility Types

Answer 34

Predefined types like Partial, Readonly, Record, etc., for common transformations.

Question 35

Type Guards

Answer 35

Runtime checks to ensure a variable matches a specific type.

Question 36

Abstract Classes

Answer 36

Classes that cannot be instantiated but can be extended.

Question 37

Promises in TypeScript

Answer 37

Handle asynchronous operations with typed Promises.

Question 38

Error Handling

Answer 38

Use try-catch blocks with type-safe error objects.

Question 39

Compatibility with JS

Answer 39

TypeScript is fully compatible with existing JavaScript code.

Question 40

DOM Manipulation

Answer 40

Type-safe interaction with HTML elements using TypeScript.

Question 41

Function Overloading

Answer 41

Define multiple function signatures for one implementation.

Question 42

Constructor

Answer 42

Special method in classes for initializing objects.

Question 43

Static Members

Answer 43

Class-level properties or methods shared across all instances.

Question 44

TypeScript Playground

Answer 44

Online editor to experiment with TypeScript code.

Question 45

Tooling Support

Answer 45

Integrated into many IDEs like VS Code for autocompletion and type checking.

Question 46

Code Refactoring

Answer 46

Simplified and safer refactoring with static type checking.

Question 47

Community Support

Answer 47

Growing community and resources for TypeScript developers.

Question 48

Migration

Answer 48

Easily migrate JavaScript projects incrementally to TypeScript.