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Rust’s default assumption is that every value can move. Assignment moves, function calls move, returning from a function moves. For the vast majority of types this is harmless: a String owns a heap allocation and the pointer to that allocation travels with the struct when it moves. But some types contain pointers into their own…
Rust’s asm! macro is the language’s escape hatch into the raw instruction set of the machine. It exists because some operations cannot be expressed in portable Rust, and some optimizations require control that even LLVM’s best efforts cannot provide. This chapter is about using that escape hatch responsibly: writing inline assembly that is correct, that…
Static Site Generation produces the HTML for every route at build time. Each URL maps to a file on disk that a CDN can serve from cache in tens of milliseconds, regardless of where the user is or how many other requests are in flight. The server does no work per request, so Time to…
Hydration has historically been an all-or-nothing operation. The server sends HTML, the browser parses it, and React attaches event handlers to the entire tree before any part of the page becomes interactive. In a large application, the JavaScript bundle can be hundreds of kilobytes, and the main thread can be blocked for hundreds of milliseconds…
Hydration mismatches occur when the HTML generated by the server does not match what React expects during the client’s initial render. React’s hydrateRoot treats this as a bug, not a feature. In development, it warns about the mismatch; in production, it may fall back to client rendering from the nearest Suspense boundary, which discards the…
React does not attach event listeners to the DOM elements you write in JSX. It attaches a single listener per event type to the root container, and when a native event fires, React walks its internal Fiber tree to find the components that have handlers for that event, then calls them with a SyntheticEvent—a cross-browser…
A React memory leak is not a failure of React’s garbage collection. React unmounts the component, removes its DOM, and drops its internal references. The leak persists because something outside React still holds a reference to the component’s state, its DOM nodes, or its closures. The common sources are timers, event listeners on window or…
A quick-reference for Vue 3 APIs, reactivity, components, and internals. Organized for lookup, not for reading. Component Definition Syntax Meaning <script setup> Composition API, compiled to setup() defineComponent({}) Options API with TS support export default {} Options API object <script setup lang=”ts”> TypeScript + Composition API <script setup vapor> Vapor Mode component (Vue 3.6+) Reactivity:…
The mount phase, the render pipeline, and the scheduler queue are three stages of the same mechanism. The mount phase creates the component instance, runs the setup, and executes the render function for the first time. The render pipeline turns the template into a virtual DOM tree and patches it into real DOM nodes. The…
Vue’s template compiler is not a closed pipeline. The transform stage—the phase between parsing the template into an AST and generating the render function—is built from an array of nodeTransforms functions that run on every node, and a map of directiveTransforms that run on specific directives. A custom compiler plugin is a function inserted into…