Function ingestTemplate

packages/compiler/src/template/pipeline/src/ingest.ts:448–505

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

(unit: ViewCompilationUnit, tmpl: t.Template)

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

  const childView = unit.job.allocateView(unit.xref);

  let tagNameWithoutNamespace = tmpl.tagName;
  let namespacePrefix: string | null = '';
  if (tmpl.tagName) {
    [namespacePrefix, tagNameWithoutNamespace] = splitNsName(tmpl.tagName);
  }

  const i18nPlaceholder = tmpl.i18n instanceof i18n.TagPlaceholder ? tmpl.i18n : undefined;
  const namespace = namespaceForKey(namespacePrefix);
  const functionNameSuffix =
    tagNameWithoutNamespace === null ? '' : prefixWithNamespace(tagNameWithoutNamespace, namespace);
  const templateKind = isPlainTemplate(tmpl)
    ? ir.TemplateKind.NgTemplate
    : ir.TemplateKind.Structural;
  const templateOp = ir.createTemplateOp(
    childView.xref,
    templateKind,
    tagNameWithoutNamespace,
    functionNameSuffix,
    namespace,
    i18nPlaceholder,
    tmpl.startSourceSpan,
    tmpl.sourceSpan,
  );
  unit.create.push(templateOp);

  ingestTemplateBindings(unit, templateOp, tmpl, templateKind);
  ingestReferences(templateOp, tmpl);
  ingestNodes(childView, tmpl.children);

  for (const {name, value} of tmpl.variables) {
    childView.contextVariables.set(name, value !== '' ? value : '$implicit');
  }

  // If this is a plain template and there is an i18n message associated with it, insert i18n start
  // and end ops. For structural directive templates, the i18n ops will be added when ingesting the
  // element/template the directive is placed on.
  if (templateKind === ir.TemplateKind.NgTemplate && tmpl.i18n instanceof i18n.Message) {
    const id = unit.job.allocateXrefId();
    ir.OpList.insertAfter(
      ir.createI18nStartOp(id, tmpl.i18n, undefined, tmpl.startSourceSpan),
      childView.create.head,
    );
    ir.OpList.insertBefore(
      ir.createI18nEndOp(id, tmpl.endSourceSpan ?? tmpl.startSourceSpan),
      childView.create.tail,
    );
  }
}