Interview Questions
TypeScript is a statically typed superset of JavaScript developed by Microsoft. It adds optional static
types, interfaces, and type annotations to JavaScript, allowing developers to catch errors during
development rather than at runtime. TypeScript code is transpiled into plain JavaScript, making it
compatible with any JavaScript environment, including browsers, Node.js, and more
TypeScript is a statically typed superset of JavaScript that adds optional static types, interfaces, and
type checking. It compiles down to plain JavaScript, making it compatible with all browsers. The primary
difference is that TypeScript introduces type safety, making code easier to understand, refactor, and
debug.
Early detection of errors through static type checking.
Improved code readability and maintainability.
Enhanced tooling support (e.g., autocompletion, refactoring).
Ability to use modern JavaScript features even in environments that don't support them directly (thanks to
transpilation).
Support for object-oriented programming concepts like interfaces, generics, and inheritance.
An interface in TypeScript defines a contract for an object or a class. It specifies the properties and
methods that an object must implement. Interfaces allow for strong type checking and are particularly
useful in defining complex data structures.
Generics allow you to create reusable components that work with various types rather than a single one.
Generics provide a way to define functions, classes, and interfaces that can work with different data
types.
Type aliases are used to create a new name for an existing type or a union of types. They are similar to
interfaces but are more flexible since they can represent any type, not just object types.
TypeScript supports modern ES6/ES7 features like async/await, classes, modules, destructuring, and more.
When you write TypeScript code using these features, it gets transpiled into ES5 or a lower version of
JavaScript, depending on the target configuration in the tsconfig.json file.
never: Represents a value that never occurs. It is used in functions that never return (e.g., functions
with an infinite loop or those that always throw an error).
unknown: A type-safe counterpart to any. It requires a type assertion or checking before using it,
ensuring more type safety than any.
You can make properties optional by appending a question mark (?) to the property name in an interface or
type alias.
Decorators are a special kind of declaration that can be attached to a class, method, accessor, property,
or parameter. They are used to modify the behavior of the element to which they are attached. Decorators
are declared with an @ symbol and are often used in frameworks like Angular.
