TypeScript simple patterns for Web Developers

Introduction

TypeScript is a typed superset of JavaScript that adds static type checking to the language. This can help to prevent errors and make code more maintainable. In this article, I will share 5 of the most useful TypeScript patterns for web developers. These patterns can help you to write more concise, reusable, and maintainable code.

The pattern list

1. Using interfaces to define types

interface User {
  name: string;
  email: string;
}

const user: User = {
  name: "John Doe",
  email: "[e-mail]",
};

This code snippet shows how to use interfaces to define types in TypeScript. This can help to prevent errors and make code more maintainable.

Full documentation of interfaces here

1. Using generics to create reusable code

function createList<T>(items: T[]) {
  return items.map((item) => item);
}

const listOfStrings = createList(["hello", "world"]);
const listOfNumbers = createList([1, 2, 3]);

This code snippet shows how to use generics to create reusable code in TypeScript. This can help to make code more concise and easier to understand.

Full documentation of generics here

1. Using enums to represent sets of values

enum Direction {
  Up = "UP",
  Down = "DOWN",
  Left = "LEFT",
  Right = "RIGHT",
}

const myDirection = Direction.Up;

This code snippet shows how to use enums to represent sets of values in TypeScript. This can help to make code more readable and easier to maintain.

Full documentation of enum here

1. Using modules to organize code

module MyModule {
  export function sayHello() {
    return "Hello, world!";
  }
}

import { sayHello } from "MyModule";

const message = sayHello();

This code snippet shows how to use modules to organize code in TypeScript. This can help to make code more modular and easier to understand.

Full documentation of modules here

1. Using type guards to check the type of a variable

function sayHello(name: string) {
  if (typeof name === "string") {
    return `Hello, ${name}!`;
  } else {
    return "Invalid name";
  }
}

This code snippet shows how to use type guards to check the type of a variable in TypeScript. This can help to prevent errors and make code more robust.

Full documentation of decorators here

1. Using functional programming techniques

const double = (x: number) => x * 2;

const myNumber = double(10);

This code snippet shows how to use functional programming techniques. The double function takes a number as input and returns the number multiplied by 2. This is a more concise and elegant way of writing code than using traditional imperative programming techniques.

Full documentation of functions here

1. Using decorators to add metadata to code)

@Decorator()
class MyClass {
  // ...
}

const myInstance = new MyClass();

This code snippet shows how to use decorators to add metadata to code in TypeScript. This can help to make code more extensible and easier to understand.

Full documentation of decorators here

Conclusion:

These are just 5 of the many TypeScript patterns that can be used by web developers. By using these patterns, you can write more concise, reusable, and maintainable code.

I hope this article has been helpful!