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.
Immutability is the practice of never modifying a value after it is created. Instead of changing an object, you create a new one with the change applied. This sounds like a small discipline, but it has large consequences: immutable data is safe to share, safe to compare by reference, safe to use in concurrent contexts,…
A Vue component is a function that returns a UI. A composable is a function that returns state and behavior, without the UI. The two are the same kind of thing, and the distinction is where the logic lives. When the logic is inside a component, it is bound to that component’s template. When the…
A signal-based component is a component whose state is expressed with signals, whose inputs are signals, whose outputs are signal-aware, and whose template reads the signals directly. The change detection is driven by the signals, and the component is checked only when the signals it reads change. The model is the modern Angular, and it…
These three functions are the individual axis scaling functions in CSS transforms. Each one scales an element along a specific axis: X (horizontal), Y (vertical), or Z (depth). Overview of Functions Function Axis Equivalent Effect scaleX() Horizontal scale3d(s, 1, 1) Stretches width scaleY() Vertical scale3d(1, s, 1) Stretches height scaleZ() Depth scale3d(1, 1, s) Stretches…
A unit test should test one thing. When the unit under the test depends on the database, the network, the clock, or the file system, the test must isolate the unit from those dependencies. Otherwise the test is slow, flaky, and coupled to the external systems. Test doubles are the objects that stand in for…
A Docker host accumulates garbage. The stopped containers linger, the dangling images pile up, the build cache grows, and the unused volumes sit idle. The disk fills slowly, and then suddenly the builds fail, the pulls fail, and the daemon stops responding. The cleanup is not a one-time task; it is the ongoing maintenance. The…
JavaScript has one number type — a 64-bit floating-point value. There’s no separate integer type (except BigInt). Understanding how it behaves — including its limits and quirks — is essential for writing correct numeric code. Key point: All JavaScript numbers are IEEE 754 double-precision floating-point. This means integers up to 2^53 are exact, but floating-point…
A traditional session lives on the server. The user logs in, the server creates the session record, and the session ID goes into the cookie. The next request carries the cookie, and the server looks up the session in the store. The lookup is the state, and the state is the scaling problem: the session…
A React application has two kinds of updates. The first is the urgent update: the user types a character, clicks a button, presses a key. The response must be immediate, or the interface feels broken. The second is the non-urgent update: the search results filter, the chart recalculates, the tab content loads. The response can…
A closure captures the variables it uses from the surrounding scope. By default, the compiler infers the least restrictive capture: an immutable borrow if the closure only reads the variable, a mutable borrow if it modifies it, and a move if the closure takes ownership. The inference is convenient for the closures that are called…