TypeScript is a superset of JavaScript that adds static typing and other features to the language.
What are the benefits of using TypeScript?
TypeScript offers static typing, which helps catch errors early in development.
It enhances code readability and maintainability.
It provides better tooling support and helps in refactoring.
Explain the difference between let and const in TypeScript.
let is used to declare variables that can be reassigned, while const is used for variables whose value cannot be changed once assigned.
What are interfaces in TypeScript?
Interfaces in TypeScript are used to define the structure of objects. They specify the properties and methods that an object must have.
What is the use of access modifiers in TypeScript?
Access modifiers (public, private, and protected) control the accessibility of class members in TypeScript. They define how these members can be accessed from outside the class.
Explain what is a decorator in TypeScript.
Decorators are a design pattern used to modify the behavior of class members or methods at runtime. In TypeScript, decorators are declared using the @ symbol.
What is a namespace in TypeScript?
Namespaces in TypeScript are used to organize code and prevent naming collisions. They provide a way to group related code under a unique identifier.
How do you handle asynchronous operations in TypeScript?
Asynchronous operations in TypeScript can be handled using promises, async/await, or observables (for RxJS).
What is the use of generics in TypeScript?
Generics allow you to create reusable components and functions that can work with a variety of data types. They enable type safety and flexibility in TypeScript.
Explain the concept of type assertion in TypeScript.
Type assertion is a way to tell the TypeScript compiler that you know more about the type of a value than it does. It is similar to type casting in other languages.
What are union types in TypeScript?
Union types allow a variable to have multiple types. They are denoted using the | symbol between the types.
How do you declare optional properties in TypeScript interfaces?
Optional properties in TypeScript interfaces are declared by appending a ? to the property name.
What is the readonly modifier in TypeScript?
The readonly modifier in TypeScript is used to make properties immutable. Once assigned a value, a readonly property cannot be changed.
Explain the never type in TypeScript.
The never type represents values that never occur. It is used to indicate that a function never returns or that a variable is never assigned a value.
What are type guards in TypeScript?
Type guards are used to narrow down the type of a variable within a conditional block. They help TypeScript understand the type of a variable more accurately.
What is a tuple in TypeScript?
A tuple is an array-like structure in TypeScript that allows you to specify the type of each element at different positions. Tuple types enable you to work with fixed-size arrays with a known type for each position.
Explain the concept of enums in TypeScript.
Enums in TypeScript allow you to define a set of named constants. They provide a way to represent a group of related values as a single type.
How do you handle null and undefined in TypeScript?
TypeScript provides the --strictNullChecks compiler flag to handle null and undefined values more strictly. Additionally, you can use type unions or optional chaining to deal with potentially nullable values.
What are modules in TypeScript?
Modules in TypeScript are used to organize code into reusable components. They provide encapsulation and allow you to define dependencies between different parts of your application.
Explain the difference between export default and named exports in TypeScript.
export default is used to export a single value or function from a module, while named exports are used to export multiple values or functions with specific names.
How do you import modules in TypeScript?
Modules can be imported in TypeScript using the import keyword followed by the module name.
What is a type alias in TypeScript?
A type alias in TypeScript allows you to create a custom name for any data type. It is useful for creating complex types or simplifying type annotations.
What is the keyof keyword in TypeScript?
The keyof keyword in TypeScript is used to get the keys of an object type as a union of string literals.
How do you create an array of a specific type in TypeScript?
You can create an array of a specific type in TypeScript using type annotations, generics, or type assertions.
What is the difference between Array and [] in TypeScript?
Array<T> is a built-in generic type in TypeScript for defining arrays, while [] is shorthand notation for defining arrays with a specific type.
How do you define a function type in TypeScript?
Function types in TypeScript can be defined using arrow functions, function declarations, or function expressions with type annotations.
What are ambient declarations in TypeScript?
Ambient declarations in TypeScript are used to define the shape of external libraries or APIs without actually implementing them. They are typically declared using the declare keyword.
What is the this keyword in TypeScript?
The this keyword in TypeScript refers to the current instance of an object within a function or method. Its type can be explicitly annotated to ensure type safety.
How do you create an interface for a function type in TypeScript?
You can create an interface for a function type in TypeScript using the interface keyword followed by the signature of the function.
Explain the as const assertion in TypeScript.
The as const assertion in TypeScript is used to infer the most specific literal type for a value. It tells the compiler to treat a value as read-only and narrow down its type to its exact value.
