Concepts

How it works

• Reactivity model: Signals, memos, effects, derived constants and stores as one dependency graph, and the exact rules for what is tracked.
• Ownership: How effects, memos, cleanups and errors belong to an owner tree, in which order disposal runs, and what the NO_OWNER diagnostics mean.
• Scheduler and timing: Exactly when signal and store writes reach effects and the DOM, in which order effects run, and what stops an effect loop.
• Fine-grained rendering: What the compiler turns JSX into (template, insert, effect, delegated events), why no virtual DOM exists, and why the live DOM contains no comment nodes.
• Reconciliation: How arrays given to insert and For are reconciled against the DOM, which nodes move and which are created, and how keyed and unkeyed lists differ.
• Hydration keys: The deterministic key algorithm that lets the client claim server-rendered DOM, the region markers in server HTML, resource keys, and why keys never depend on owners, effects or memos.