Function parseSync

xml/_parse_sync.ts:88–1471

(xml: string, options?: ParseOptions)

 * @throws {XmlSyntaxError} If the XML is malformed.
 */
export function parseSync(xml: string, options?: ParseOptions): XmlDocument {
  const ignoreWhitespace = options?.ignoreWhitespace ?? false;
  const ignoreComments = options?.ignoreComments ?? false;
  const trackPosition = options?.trackPosition ?? true;
  const disallowDoctype = options?.disallowDoctype ?? true;
  const maxDepth = options?.maxDepth ?? Infinity;
  const maxAttributes = options?.maxAttributes ?? Infinity;
  const xml11 = options?.xmlVersion === "1.1";

  // Normalize line endings (XML 1.0 §2.11 / XML 1.1 §2.11)
  const version = xml11 ? "1.1" : "1.0";
  const needsNormalization = xml11
    ? xml.includes("\r") || xml.includes("\x85") || xml.includes("\u2028")
    : xml.includes("\r");
  const input = needsNormalization
    ? xml.replace(LINE_ENDING_REGEXP[version], "\n")
    : xml;
  const len = input.length;

  function isIllegalLiteralChar(code: number): boolean {
    return isIllegalXmlLiteralChar(code, xml11);
  }

  // Parser state - only track position offset, not line/column
  let pos = 0;

  // Tree building state
  const stack: MutableElement[] = [];
  let root: MutableElement | undefined;
  let declaration: XmlDeclarationEvent | undefined;
  let rootClosed = false; // Track whether root element has been closed

  // Namespace tracking (lazy initialization for performance)
  // Only created when first namespace prefix is encountered
  // Using object wrapper to avoid TypeScript control flow narrowing issues with error()
  const ns: { bindings: Map<string, string> | null } = { bindings: null };
  // Stack of namespace bindings per element scope (array of [prefix, previousUri] tuples)
  // Used to restore bindings when element closes
  const nsStack: Array<Array<[string, string | undefined]>> = [];
  // Reusable empty array to avoid allocations for elements without namespace bindings
  const EMPTY_NS_SCOPE: Array<[string, string | undefined]> = [];

  /** Get or create namespace bindings map with xml prefix pre-bound */
  function getNsBindings(): Map<string, string> {
    if (!ns.bindings) {
      ns.bindings = new Map([["xml", XML_NAMESPACE]]);
    }
    return ns.bindings;
  }

  // Note: We do NOT expand custom entities from DTD.
  // We only support the 5 predefined XML entities: lt, gt, amp, apos, quot.
  // External entities (SYSTEM/PUBLIC) are also not supported.

  /**
   * Compute line and column from offset on-demand (lazy position tracking).
   * Only called when an error occurs, avoiding overhead during successful parsing.
   */