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A Beginner's Guide to TypeScript

Published on July 31, 2020


TypeScript is a statically typed superset of JavaScript that allows developers to catch errors early and add structure to their code. In this post, we will explore the basics of TypeScript and how it can be used to improve your frontend development workflow.

What is TypeScript?

TypeScript is a programming language developed by Microsoft. It adds optional static typing and other features to JavaScript to make it a more powerful and maintainable language. TypeScript is designed to help developers catch errors early in the development process, making it easier to write, test, and maintain their code.

Why Use TypeScript?

Using TypeScript can provide several benefits for frontend developers, including:

  1. Better code readability: With TypeScript, you can add type annotations to your code, which makes it easier for other developers to understand the purpose of each variable and function. This can also help catch errors early in the development process.
  2. Code completion and autocompletion: When using TypeScript, you can take advantage of features like code completion and autocompletion in your IDE or text editor. This means you can start typing a variable name and have your IDE suggest the correct type based on the type annotations you’ve provided.
  3. Better error handling: TypeScript allows you to catch errors early in the development process, before they become more difficult to fix. You can use type annotations to specify which types are allowed for each variable or function, which helps prevent unexpected data from being passed around your codebase.
  4. Improved maintainability: With TypeScript, you can add structure to your code and make it easier to maintain over time. This can help prevent bugs and make changes to your code easier to understand and review.
  5. Compatibility with JavaScript: While TypeScript is a separate language from JavaScript, it is designed to be fully compatible with existing JavaScript projects. This means you can use TypeScript alongside your existing JavaScript codebase without any issues.

Getting Started with TypeScript

To get started with TypeScript, you’ll need to install the necessary dependencies for your project. The most common way to do this is by using a package manager like npm or yarn. Once you have the dependencies installed, you can create a new TypeScript file and start writing your code.

Basic Types in TypeScript

In TypeScript, there are several basic types that you can use to define variables and function parameters. These include:

  1. number: Represents a numeric value, such as 3 or 42.
  2. string: Represents a string of text, such as “hello” or “goodbye”.
  3. boolean: Represents a true or false value.
  4. array: Represents an array of values, such as [1, 2, 3] or [“apple”, “banana”, “orange”].
  5. object: Represents an object with properties and methods, such as { name: “John”, age: 30 }.
  6. function: Represents a function that can be called with arguments and returns a value.
  7. void: Represents the absence of a return type, which means that the function does not return any value.
  8. any: Represents an unknown type, which means that you can assign any type to this variable or parameter.
  9. null and undefined: These types represent the absence of a value, which is often used as a placeholder when no other value is available.

Advanced Types in TypeScript

In addition to basic types, TypeScript also has several advanced types that you can use to define more complex data structures. These include:

  1. enums: Represents a set of named values, such as { “red”, “green”, “blue” }.
  2. interfaces: Represents a set of properties and methods that must be implemented by any object that implements the interface.
  3. type aliases: Represents an alias for another type, which can make your code easier to read and maintain.
  4. generics: Represents a placeholder for a type parameter, which can be used to create reusable functions and classes.
  5. tuples: Represents a fixed-length array of values, such as [string, number].
  6. unions: Represents a set of types that can be used interchangeably, such as string | number.
  7. intersection: Represents a set of types that must all be present in the object, such as { name: string } & { age: number }.
  8. type assertions: Represents a way to override the type system and force TypeScript to believe that an expression has a certain type, even if it can’t infer its type automatically.


TypeScript is a powerful tool for frontend developers that allows you to catch errors early in the development process, make your code more readable and maintainable, and improve your productivity overall. Whether you’re starting a new project or looking to add structure to an existing codebase, TypeScript can help you write better code and make your life easier.