Tutorials covering programming languages, type systems, architecture, tooling, and the patterns used to build software that lasts. Each chapter is standalone, built around real examples and verified facts.
A pattern is a description of a value’s shape. Pattern matching is the operation of checking whether a value has that shape and extracting the parts. Dart 3 introduced patterns as a first-class feature, and they appear in four places: variable declarations, assignments, switch statements and expressions, and for loops. The patterns destructure lists, maps,…
The host network driver removes the network namespace from the container. The container shares the host’s network stack directly, with the host’s IP address, the host’s interfaces, and the host’s ports. There is no NAT, no virtual bridge, and no port mapping. The container’s application binds to the host’s port directly, and the performance is…
Class inheritance allows you to create a new class that inherits properties and methods from an existing class. The new class (subclass/child) can reuse, extend, or override the behavior of the parent class (superclass/base). A Quick Look at the Example a. What is Class Inheritance? Inheritance is a mechanism where one class (the subclass or…
The previous chapter covered request body parsing for JSON, URL-encoded, and raw content types. The multipart/form-data format—the one the browser uses for file uploads—is a separate problem. It is a binary format with boundaries, headers per part, and file streams. Express does not parse it, and the built-in parsers do not touch it. The multer…
Fetching data is the most common side effect in a React application. A component mounts, it needs data from a server, it shows a loading state, the data arrives, it shows the data. The pattern is simple to describe and full of traps: the effect that fetches can run twice, the response can arrive after…
A function that can fail has to tell the caller. Rust’s mechanism for this is Result<T, E>, an enum with two variants: Ok(T) for success and Err(E) for failure. The Result is not an exception. It is a value. The caller receives it, inspects it, and decides what to do. The compiler checks that the…
A relational database stores data in separate tables to avoid redundancy. Customers live in one table, orders in another, products in a third. Each table holds only the data relevant to its entity, and relationships between entities are represented by shared keys: an order row contains a customer_id that points to a customer row. A…
A variant applies a utility when a condition is true. The not-* variant applies a utility when a condition is false. It is the negation of a pseudo-class, and it is the tool for the styling that needs to apply to everything except a specific state or position. The not-first:mt-4 applies a top margin to…
A template literal type is a type built from a string template — the same backtick syntax as JavaScript, but at the type level. It lets you describe strings that match a pattern: \get${string}`, `${number}px`, `${Uppercase}Id`. Combined with unions and infer`, template literal types can split strings, generate combinations, rename keys, and validate formats. They’re…
A component often needs more than one two-way binding. A form component has a first name and a last name. A date-range picker has a start date and an end date. A filter panel has a search term and a category. A settings component has a theme and a language. Each of these is a…