How 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.
Jonah Vail
JS Ledger
JS Ledger examines JavaScript, TypeScript, and the runtimes, frameworks, and tooling behind modern web applications.
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All postsReading a Lockfile: Supply Chain in Practice
What package-lock.json actually records, what its integrity hashes do and do not prove, and where the real install-time risk sits.
Type-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.
The 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.
What 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.
Signals 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.