Runtime Model

StAX-XML is distributed as a pure JavaScript package. There is no optional native addon, Wasm parser module, or backend selection step to install or tune. The same package is intended to run across Node.js, Bun, Deno, browsers, and edge runtimes.

This matters because the public API returns JavaScript values: strings, attributes, event objects, arrays, and converter output objects. A lower-level scanner can sometimes find XML token boundaries faster, but those parsed values still have to become JavaScript strings and objects before user code can consume them.

Keeping the parser in JavaScript makes the tradeoff explicit:

• install and runtime behavior stay portable;
• memory accounting stays inside the JavaScript runtime as much as possible;
• large XML workloads avoid whole-document string materialization;
• pull-style readers can expose events incrementally without DOM state.

For workloads that need lower allocation overhead, use StreamReader or StreamReaderSync and consume each batch with eventCount plus index accessors. For ergonomic application code, use EventReader, EventReaderSync, or converter schemas.

Detailed runtime-engine notes belong outside the package docs. The public docs describe the supported package model and the API surfaces users can rely on.