TypeScript Interview Questions and Answers
Freshers / Beginner level questions & answers
Ques 1. What is TypeScript?
TypeScript is a superset of JavaScript that adds static typing and other features to the language.
Ques 2. Explain the difference between 'let' and 'const' in TypeScript.
'let' is used to declare variables with block scope, while 'const' is used to declare constants with block scope that cannot be reassigned.
Ques 3. What are the basic data types in TypeScript?
The basic data types in TypeScript are number, string, boolean, null, undefined, and object.
Ques 4. How do you define an interface in TypeScript?
Interfaces in TypeScript are defined using the 'interface' keyword, followed by the interface name and a set of property declarations.
Ques 5. What is the 'any' type in TypeScript?
The 'any' type in TypeScript is used to represent a dynamic type that can hold values of any type, and it bypasses type checking.
Ques 6. How do you declare an array in TypeScript?
Arrays in TypeScript can be declared using the syntax 'let myArray: number[] = [1, 2, 3];' or 'let myArray: Array
Ques 7. How do you handle errors in TypeScript?
Errors in TypeScript can be handled using try-catch blocks, similar to JavaScript.
Ques 8. How do you use optional parameters in TypeScript?
Optional parameters in TypeScript are denoted by adding a '?' after the parameter name in the function declaration.
Ques 9. What is the 'readonly' modifier in TypeScript?
The 'readonly' modifier in TypeScript is used to make properties of an object immutable after their initial assignment.
Ques 10. Explain the concept of union types in TypeScript.
Union types in TypeScript allow a variable to hold values of multiple types, separated by the '|' symbol.
Ques 11. How do you declare and use a class in TypeScript?
Classes in TypeScript are declared using the 'class' keyword, and objects are created using the 'new' keyword.
Ques 12. What is the 'for...of' loop in TypeScript?
The 'for...of' loop in TypeScript is used to iterate over the values of an iterable object, such as an array or a string.
Ques 13. How do you use the 'import' statement in TypeScript?
The 'import' statement in TypeScript is used to import modules or exports from other files.
Ques 14. How do you use the 'in' operator in TypeScript?
The 'in' operator in TypeScript is used to check if a property exists in an object.
Ques 15. What is the 'Tuple' type in TypeScript?
A tuple in TypeScript is a fixed-size, ordered list of elements where each element can have a different type.
Ques 16. What is the purpose of the 'export' keyword in TypeScript?
The 'export' keyword in TypeScript is used to make functions, variables, or classes available for use in other files by importing them.
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