Typescript Programming Tutorials, Guides & Best Practices

Let's see how these advanced techniques can be applied to a real-world scenario. We'll create a reusable React component that can handle different types of form fields.

import React from "react";

type FormFieldProps<T> = {
  value: T;
  onChange: (value: T) => void;
};

function FormField<T>({ value, onChange }: FormFieldProps<T>) {
  return (
    <input
      type="text"
      value={String(value)}
      onChange={(e) => onChange(e.target.value as unknown as T)}
    />
  );
}

// Usage
const App = () => {
  const [name, setName] = React.useState<string>("");
  const [age, setAge] = React.useState<number>(0);

  return (
    <div>
      <FormField value={name} onChange={setName} />
      <FormField value={age} onChange={setAge} />
    </div>
  );
};

export default App;

You can provide default types for generics, which will be used if no type is specified.

function createArray<T = string>(length: number, value: T): T[] {
  return Array(length).fill(value);
}

const stringArray = createArray(3, 'x'); // string[]
const numberArray = createArray<number>(3, 42); // number[]

my-vscode-extension/

 .vscode/                # VS Code specific settings
 src/                    # Source code for your extension
    extension.ts        # Main entry point for your extension
 .gitignore              # Git ignore file
 .eslintrc.json          # Linting configuration
 package.json            # Extension manifest and dependencies
 tsconfig.json           # TypeScript configuration
 README.md               # Documentation for your extension

VS Code extensions often start by adding new commands. Let’s create a simple command that displays a message when executed.

Introduction

TypeScript is a statically typed superset of JavaScript that brings optional types, interfaces, and modern JavaScript features to the table. It has become increasingly popular due to its ability to catch errors early in the development process, enhance code maintainability, and improve overall developer productivity. In this comprehensive guide, we’ll explore TypeScript from the ground up, covering everything from basic syntax to advanced concepts like generics, decorators, and TypeScript configuration.

npm install --save-dev typescript

Or with yarn: