Function computePosition

xml/_parse_sync.ts:146–169

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

(offset: number)

   * Only called when an error occurs, avoiding overhead during successful parsing.
   */
  function computePosition(offset: number): {
    line: number;
    column: number;
    offset: number;
  } {
    if (!trackPosition) {
      return { line: 0, column: 0, offset: 0 };
    }
    let line = 1;
    let lastNlPos = -1;
    let searchStart = 0;
    while (true) {
      const nlPos = input.indexOf("\n", searchStart);
      if (nlPos === -1 || nlPos >= offset) break;
      line++;
      lastNlPos = nlPos;
      searchStart = nlPos + 1;
    }
    return {
      line,
      column: offset - lastNlPos,
      offset,
    };
  }

  function error(message: string): never {
    throw new XmlSyntaxError(message, computePosition(pos));