Development

In the previous tutorial, we learned about objects and interfaces. Now let’s learn about union types, literal types, and type aliases — patterns that make TypeScript truly powerful. By the end of this tutorial, you will know how to use union types, literal types, discriminated unions, intersection types, and type aliases. Union Types A union type means “this value can be one of several types.” Use the | (pipe) symbol: let id: string | number; id = "abc-123"; // OK — string id = 42; // OK — number id = true; // Error: Type 'boolean' is not assignable to type 'string | number' Union types are everywhere in real code. A function that accepts multiple types: ...

In the previous tutorial, we learned how to type functions. Now let’s learn how to describe the shape of objects — one of the most important skills in TypeScript. By the end of this tutorial, you will know how to define object types, use interfaces, extend them, and choose between interfaces and type aliases. Object Types You can describe an object’s shape by listing its properties and types: let user: { name: string; age: number } = { name: "Alex", age: 25, }; TypeScript checks that the object matches the shape: ...

In the previous tutorial, we learned the basic types in TypeScript. Now let’s learn how to use types with functions — the building blocks of every program. By the end of this tutorial, you will know how to type every kind of function in TypeScript. Function Parameter Types In TypeScript, you must add types to function parameters. TypeScript cannot infer parameter types: // JavaScript — no types function greet(name) { return "Hello, " + name; } // TypeScript — types required function greet(name: string) { return "Hello, " + name; } If you forget to add a type, TypeScript gives an error with strict: true: ...

In the previous tutorial, we installed TypeScript and wrote our first program. Now let’s learn the type system — the core feature that makes TypeScript useful. By the end of this tutorial, you will know every basic type in TypeScript and when to use each one. Type Annotations A type annotation tells TypeScript what type a variable should be. You add it after the variable name with a colon: let name: string = "Alex"; let age: number = 25; let isActive: boolean = true; The : string, : number, and : boolean are type annotations. If you try to assign the wrong type, TypeScript gives an error: ...

A prompt that works on three examples might fail on the fourth. Prompt engineering without testing is guessing. In this article, you will learn how to test prompts systematically, measure quality, and iterate until you get reliable results. This is Article 18 in the Claude AI — From Zero to Power User series. You should know Prompt Engineering Basics before this article. By the end, you will have an eval harness that tests your prompts automatically and a process for improving them. ...

In the previous tutorial, we learned what TypeScript is and why it matters. Now let’s install it and write our first program. By the end of this tutorial, you will have TypeScript installed, VS Code configured, and a working project you built yourself. Step 1: Install Node.js TypeScript runs on Node.js. If you don’t have Node.js installed, download the LTS version from nodejs.org. After installation, verify it works: node --version # v22.x.x or later npm --version # 10.x.x or later If both commands print version numbers, you are ready. ...

TypeScript is everywhere. It became the #1 most-used language on GitHub in August 2025, surpassing Python. It now ranks among the top languages in every major developer survey. If you write JavaScript, TypeScript is no longer optional — it is expected. This tutorial series will take you from zero to confident TypeScript developer. We start here: what TypeScript actually is, and why you should learn it in 2026. What is TypeScript? TypeScript is a superset of JavaScript that adds static types. Every valid JavaScript file is already valid TypeScript. TypeScript just adds extra features on top. ...

In the previous tutorial, we built a web scraper. Now let’s build an automation script — a file organizer that sorts files by type, processes CSV data, and logs everything properly. This is the final project in the Python Tutorial series. It ties together everything: file I/O, dataclasses, error handling, logging, testing, and packaging. By the end, you will have a practical tool you can use every day. What We Are Building A file organizer that: ...

In the previous tutorial, we built a REST API with FastAPI. Now let’s build a web scraper — a program that extracts data from web pages automatically. We will use httpx to fetch pages and BeautifulSoup to parse HTML. By the end, you will know how to extract data, save it to JSON and CSV, and scrape responsibly. When to Scrape (and When Not To) Web scraping is useful for: Collecting data that is not available via an API Monitoring prices, job listings, or news Research and data analysis But check these first: ...

In the previous tutorial, we built a CLI tool with Click and Rich. Now let’s build a REST API — a web API that any frontend, mobile app, or other service can call. We will use FastAPI, the fastest-growing Python web framework. It has automatic documentation, type checking, and built-in validation. By the end of this tutorial, you will have a working Bookmark Manager API. Why FastAPI? Automatic API docs — Swagger UI at /docs (free, no setup) Type-safe — uses Python type hints for validation Fast — built on Starlette and Pydantic (one of the fastest Python frameworks) Async support — native async/await (from Tutorial #18) Pydantic validation — automatic input validation (from Tutorial #10) Install the dependencies: ...