@anhquoc96/fastxml

Portable XML parsing and DOM-style document APIs for Node.js and Deno.

fastxml is the core package in the fastxml family. It supports convenient tree-based XML processing and incremental parsing for large documents without runtime-specific XML dependencies.

Installation

npm install @anhquoc96/fastxml

Node.js:

import { parse, loadFile } from "@anhquoc96/fastxml";

Deno:

import { parse, parseStream } from "npm:@anhquoc96/fastxml";

Parse XML

import { parse } from "@anhquoc96/fastxml";

const document = parse(
  `<catalog xmlns="urn:example:catalog"><book id="1">XML</book></catalog>`,
);

const book = document.getElementsByTagNameNS("urn:example:catalog", "book")[0];
console.log(book.textContent); // XML
console.log(book.getAttribute("id")); // 1

The DOM API includes documentElement, childNodes, parentNode, appendChild, removeChild, cloneNode, textContent, attributes, getElementsByTagName, getElementsByTagNameNS, querySelector, and querySelectorAll.

String, file, URL, and stream inputs

import { load, loadFile, parseStream, parseUrl } from "@anhquoc96/fastxml";

const fromText = await load({ text: xmlText });
const fromFile = await loadFile("./large.xml");
const fromStream = await parseStream(response.body!);
const fromUrl = await parseUrl("https://example.com/data.xml");

parseStream accepts async iterables and Web Streams. File access is provided through runtime adapters for Node.js and Deno.

Event parsing for large XML

Use events when the application does not need a complete DOM tree:

import { parseFileEvents } from "@anhquoc96/fastxml";

for await (const event of parseFileEvents("large.xml", { preserveWhitespace: false })) {
  if (event.type === "startElement" && event.name === "record") {
    // Process records incrementally.
  }
}

Parser options

const document = parse(xmlText, {
  preserveWhitespace: false,
  strictNamespaces: true,
  maxDepth: 256,
  maxTokenLength: 16 * 1024 * 1024,
  maxAttributes: 1024,
  maxEntityExpansion: 8 * 1024 * 1024,
  allowDoctype: false,
});

External entities are never resolved. Configure explicit limits when processing untrusted or tenant-controlled XML.

Development

npm install
npm run build --workspace @anhquoc96/fastxml
npm run typecheck --workspace @anhquoc96/fastxml

License

MIT License. See the package LICENSE file.