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.
In Part 1, we covered for, while, and do…while loops. In Part 2, we’ll explore two more specialized loops: for…in (for object properties) and for…of (for iterable values). A Quick Look at the Examples a. The for…in Loop The for…in loop is used to iterate over the enumerable properties of an object. It’s particularly useful…
The EventEmitter class is the backbone of Node.js’s event-driven architecture. It provides a simple mechanism: objects emit named events, and listeners subscribe to those events and run when they are emitted. The http.Server, net.Socket, fs.ReadStream, and process objects are all EventEmitter instances, and the pattern is available to any code that extends the class. Understanding…
An npm account is the credential that separates a consumer of packages from a publisher. Creating one takes minutes, but the account that can actually publish is a different thing from the account that was just created. Publishing to the public registry requires two gates to be cleared: email verification and two-factor authentication . The…
When you write an event handler in React, the object you receive is not the browser’s native event. It is a SyntheticEvent, a wrapper that React creates around the native event. The wrapper exposes the same interface — target, preventDefault(), stopPropagation(), type — but it is a plain JavaScript object that React controls. Understanding the…
Rust gives every type one of two behaviors on assignment: it either moves or it copies. A move transfers ownership and invalidates the source. A copy duplicates the value and leaves both the source and the destination valid. The Copy and Clone traits control which behavior applies. Copy is the marker for types that can…
Every SQL query that reads data starts with SELECT. It is the statement that retrieves rows from one or more tables and returns them as a result set. The SELECT statement is part of DQL — Data Query Language — and it is the most frequently used statement in SQL. Every application that displays data,…
Flexbox has a container level and an item level. The container properties — justify-*, items-*, gap-* — control how all children are arranged. The item properties — grow, shrink, basis, and order — control how each child behaves within that arrangement. These four properties determine whether an item expands to fill space, compresses when space…
A type guard is a runtime check that tells TypeScript what type a value is. The three built-in guards are typeof (for primitives), instanceof (for class instances), and in (for object shapes). Each one performs a real JavaScript check at runtime, and TypeScript follows along — narrowing the value’s type inside the corresponding branch. They’re…
The previous chapter introduced v-model as two-way binding and mentioned three modifiers—.lazy, .number, and .trim—as adjustments to the default behavior. This chapter covers them in full. They are small. Each one changes a single aspect of how the binding works. But those aspects matter: the timing of updates, the type of the bound value, and…
A CI pipeline that installs dependencies without immutable installs is a pipeline that lies. It resolves new versions silently, rewrites the lockfile if needed, and produces a build that may not match what developers tested locally. Yarn Berry changes this default: when it detects a CI environment, it automatically enables immutable installs. A lockfile that…