Function ingestElement

packages/compiler/src/template/pipeline/src/ingest.ts:276–327

* Ingest an element AST from the template into the given `ViewCompilation`.

(unit: ViewCompilationUnit, element: t.Element)

 * Ingest an element AST from the template into the given `ViewCompilation`.
 */
function ingestElement(unit: ViewCompilationUnit, element: t.Element): void {
  if (
    element.i18n !== undefined &&
    !(element.i18n instanceof i18n.Message || element.i18n instanceof i18n.TagPlaceholder)
  ) {
    throw Error(`Unhandled i18n metadata type for element: ${element.i18n.constructor.name}`);
  }

  const id = unit.job.allocateXrefId();

  const [namespaceKey, elementName] = splitNsName(element.name);

  const startOp = ir.createElementStartOp(
    elementName,
    id,
    namespaceForKey(namespaceKey),
    element.i18n instanceof i18n.TagPlaceholder ? element.i18n : undefined,
    element.startSourceSpan,
    element.sourceSpan,
  );
  unit.create.push(startOp);

  ingestElementBindings(unit, startOp, element);
  ingestReferences(startOp, element);

  // Start i18n, if needed, goes after the element create and bindings, but before the nodes
  let i18nBlockId: ir.XrefId | null = null;
  if (element.i18n instanceof i18n.Message) {
    i18nBlockId = unit.job.allocateXrefId();
    unit.create.push(
      ir.createI18nStartOp(i18nBlockId, element.i18n, undefined, element.startSourceSpan),
    );
  }

  ingestNodes(unit, element.children);

  // The source span for the end op is typically the element closing tag. However, if no closing tag
  // exists, such as in `<input>`, we use the start source span instead. Usually the start and end
  // instructions will be collapsed into one `element` instruction, negating the purpose of this
  // fallback, but in cases when it is not collapsed (such as an input with a binding), we still
  // want to map the end instruction to the main element.
  const endOp = ir.createElementEndOp(id, element.endSourceSpan ?? element.startSourceSpan);
  unit.create.push(endOp);

  // If there is an i18n message associated with this element, insert i18n start and end ops.
  if (i18nBlockId !== null) {
    ir.OpList.insertBefore<ir.CreateOp>(
      ir.createI18nEndOp(i18nBlockId, element.endSourceSpan ?? element.startSourceSpan),
      endOp,
    );
  }
}

/**
 * Ingest an `ng-template` node from the AST into the given `ViewCompilation`.