Method load

src/document/forms/field-tree.ts:66–186

* Load and build the field tree from an AcroForm. * * This performs async resolution of all field references and widget references, * then returns a FieldTree that can be iterated synchronously. * * @param acroForm The AcroForm to load fields from * @param registry The object regis

(acroForm: FieldTreeSource, registry: ObjectRegistry)

   * @returns A fully-loaded FieldTree
   */
  static load(acroForm: FieldTreeSource, registry: ObjectRegistry): FieldTree {
    const dict = acroForm.getDict();
    const resolve = registry.resolve.bind(registry);
    const fieldsArray = dict.getArray("Fields", resolve);

    if (!fieldsArray) {
      return new FieldTree([]);
    }

    const visited = new Set<string>();
    const fields: FormField[] = [];

    // Process root fields breadth-first
    const queue: Array<{
      item: unknown;
      parentName: string;
      parent: FormField | null;
    }> = [];

    // Initialize queue with root fields
    for (let i = 0; i < fieldsArray.length; i++) {
      queue.push({
        item: fieldsArray.at(i),
        parentName: "",
        parent: null,
      });
    }

    // Process queue breadth-first
    while (queue.length > 0) {
      const entry = queue.shift();

      if (!entry) {
        continue;
      }

      const { parentName, parent } = entry;
      let { item } = entry;

      const ref = item instanceof PdfRef ? item : null;
      const refKey = ref ? `${ref.objectNumber}:${ref.generation}` : "";

      // Cycle detection
      if (refKey && visited.has(refKey)) {
        registry.addWarning(`Circular reference in form field tree: ${refKey}`);
        continue;
      }

      if (refKey) {
        visited.add(refKey);
      }

      // Resolve field dictionary
      let fieldDict: PdfDict | null = null;

      if (item instanceof PdfRef) {
        item = registry.resolve(item) ?? undefined;
      }