Discover the Power of TypeScript Generics: Write Reusable Code Efficiently

TypeScript is a powerful and popular programming language that extends JavaScript with static types. It provides developers with the tools to write safer and more maintainable code. One of TypeScript's most powerful features is generics. Generics allow you to create reusable and efficient code while maintaining type safety and preventing code duplication. In this article, we will dive into the world of TypeScript generics and explore how they can help you write better code.

What are TypeScript Generics?

Generics, a concept borrowed from other statically-typed languages like C# and Java, enable you to write reusable components that work with various types without losing type safety. In essence, generics act as placeholders for types, allowing you to define functions, classes, and interfaces that can work with different types while preserving their intended behavior.

Why Use Generics?

Generics have several benefits:

  • Type safety: Generics help maintain type safety in your code, preventing runtime errors caused by incorrect data types.
  • Code reusability: Generics allow you to write a single piece of code that works with various types, reducing code duplication.
  • Intellisense support: Many code editors, including Visual Studio Code, provide intellisense support for generics, making it easier to write and understand code that uses them.

Using Generics in TypeScript

Let's dive into some examples to see how we can use generics in TypeScript.

Generic Functions

A generic function is a function that can work with different types of arguments while maintaining type safety. Here's an example of a generic function:

function identity<T>(arg: T): T {
  return arg;

let output1 = identity<string>("myString");
let output2 = identity<number>(42);

In the above example, we define a function identity that takes an argument of type T and returns a value of type T. The <T> syntax is used to specify that this function is generic and can work with any type T.

Generic Interfaces

You can also define generic interfaces in TypeScript. Here's an example:

interface GenericArray<T> {
  [index: number]: T;

let myArray: GenericArray<number> = [1, 2, 3];

In this example, we create a generic interface GenericArray that represents an array of type T. We then create an instance of this interface with type number.

Generic Classes

TypeScript allows you to create generic classes as well. Here's an example:

class Queue<T> {
  private items: T[] = [];

  enqueue(item: T): void {

  dequeue(): T | undefined {
    return this.items.shift();

const numberQueue = new Queue<number>();
console.log(numberQueue.dequeue()); // Output: 1

In this example, we create a generic class Queue that represents a simple queue data structure. The class works with any type T.


TypeScript generics are a powerful feature that allows you to write reusable and efficient code while maintaining type safety. By using generics in your TypeScript projects, you can reduce code duplication and prevent many common type-related errors. Start leveraging the power of generics in your TypeScript code today and see the difference it makes in your development experience.

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