TypeScript - JavaScript's Superset - Quiz

You can indeed rename a JavaScript file (.js) to a TypeScript file (.ts). TypeScript is designed to be a superset of JavaScript, which means that valid JavaScript code is also valid TypeScript code. When you rename a JavaScript file to have a .ts extension, it's treated as TypeScript code by editors and tools that recognize the file extension.

However, this doesn't magically add TypeScript features to your code. The file will still be interpreted as JavaScript unless you actively start incorporating TypeScript features, such as type annotations, interfaces, and other TypeScript-specific syntax. Renaming the file is just the first step; you'll need to progressively enhance your code with TypeScript features to fully leverage the benefits of TypeScript.

TypeScript was made public by Microsoft. It was developed by Microsoft and released as an open-source programming language. TypeScript is designed to enhance JavaScript by adding static typing, interfaces, classes, and other features to help developers build more scalable and maintainable software.

TypeScript is Object-Oriented.

While TypeScript does support procedural and functional programming styles, its primary design focus is on providing features and capabilities that enhance object-oriented programming (OOP). TypeScript introduces concepts such as classes, interfaces, inheritance, and other object-oriented features to JavaScript, making it easier for developers to organize and structure their code in an object-oriented manner.

So, the most accurate classification for TypeScript is Object-Oriented, although it also incorporates elements from procedural and functional programming paradigms.

Generics in programming languages, including TypeScript, allow accepting arguments of different types.

Generics provide a way to create functions, classes, or interfaces that can work with a variety of data types while maintaining type safety. When you use generics, you can specify the type of data that a function, class, or interface will work with, and that type can vary across different invocations. This flexibility enables you to write more reusable and type-safe code.

In TypeScript, when a variable is assigned the value null, it is often given the type null. This is a specific type in TypeScript that represents the absence of an object value.

So, the correct answer would be:

None of the options.

The variable is given the type null when it is explicitly assigned the value null. If you don't want to specify a particular type, you would typically use the any type, but if you assign a value of null, TypeScript will consider the variable to have the type null.

During runtime, Dynamic Type checking is done.

Dynamic typing is a feature of some programming languages where the type of a variable is checked at runtime, as opposed to static typing where type checking is done at compile time. In dynamically typed languages, the type of a variable can change during the execution of the program, and type errors are caught at runtime. This is in contrast to static typing, where type information is checked at compile time. JavaScript, for example, is a dynamically typed language.

Type Annotations allow us to record the intended contract of the function or variable.

Type annotations in programming languages, including TypeScript, are used to specify the intended data type of a variable, the return type of a function, or the types of function parameters. They provide a way for developers to explicitly state the expected types, making the code more self-documenting and allowing tools like compilers or IDEs to perform static type checking.

While type annotations help ensure that the code adheres to the specified types, they don't directly perform casting or reassign the type of data. They serve as a form of documentation and a tool for static type checking during development.

A type system is a set of rules.

A type system in programming is a collection of rules and constraints that govern the ways in which types of values can be used in a program. It defines the set of types available, the operations permitted on those types, and how types interact with each other. The purpose of a type system is to prevent the occurrence of certain errors, such as attempting to use a value of one type as if it were another type.

So, in the context of your question, a type system is a set of rules that define how different types of data and variables can be used in a program.

All the options you provided are valid ways of defining an enum in TypeScript, but they serve different purposes:

1. enum Enum {}: This is a standard way of defining an enum in TypeScript. It creates an enum named Enum with no values. You can add enum members inside the curly braces.

   
   enum Enum {
     Value1,
     Value2,
     Value3,
   }
   
   

2. const enum DNA {}: This defines a const enum, where the enum is inlined at compile time. This means that the enum values are directly substituted in the generated JavaScript code, and no runtime object is created for the enum.

   
   const enum DNA {
     Adenine,
     Thymine,
     Cytosine,
     Guanine,
   }
   
   

   Note: Const enums cannot have computed or non-constant enum members.

3. declare enum Enum {}: This is used to declare an enum that may be defined elsewhere (e.g., in an external JavaScript library). It tells TypeScript to expect that the enum is defined at runtime, even though the actual definition may not be available in the TypeScript code.

   
   declare enum Enum {
     Value1,
     Value2,
     Value3,
   }
   
   

Choose the option that best suits your needs based on whether you want a standard enum, a const enum, or if you're declaring an enum that's defined elsewhere.

Inheritance