Tag
javascript
Articles tagged “javascript”
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- №10
Language internalsYour Array Chain Called the Mapper a Million Times
Two chains return the same five numbers. One calls the mapper 1,000,000 times and allocates 13.73 MB; the other calls it 13 times and allocates nothing measurable.
- №09
The V8 object modelFour Maps Is Polymorphic. Five Is Not.
Monomorphic, polymorphic and megamorphic are counted states with a threshold of four. Here is the transition log, the V8 line that decides it, and the cost.
- №08
ReactivityYour Reactive Graph Computed 4,11. That State Never Existed.
A single-pass push through a diamond recomputes the leaf twice, and the first result mixes a fresh value with a stale one. Two passes are what remove it.
- №07
The V8 object modelObject Shapes Are a Tree, and the Tree Is Shared
A hidden class is a node in a transition tree V8 keeps for the whole isolate — which is why an unrelated function can decide how your object is stored.
- №06
Async machineryWhat await Compiles To, and What It Costs
One async function compiled three ways — TypeScript's ES5 emit, V8's bytecode and the spec's Await steps — and the microtask turns each one predicts.
- №05
The TypeScript type systemType-Level Narrowing: How TypeScript Decides What You Meant
Control flow analysis is a graph walk over your code. Knowing what widens a type again explains most of the errors that look wrong.
- №04
Async machineryThe Event Loop You Think You Know
Microtasks, rendering opportunities and starvation — what the loop actually does between your callbacks, in the browser and in Node.
- №03
The build pipelineWhat Actually Happens When Vite Serves a Module
A walk through one request to a Vite dev server: resolution, the transform pipeline, import rewriting, pre-bundling, and why production differs.
- №02
ReactivitySignals Are Not Magic: The Dependency Graph Underneath
Every signals library is the same forty lines of bookkeeping. Here is what those lines do, and where the four popular implementations diverge.
- №01
The V8 object modelHow V8 Decides to Optimize Your Function
Two functions that look identical can run at very different speeds. The difference is usually shapes, inline caches, and a deoptimization you never saw.