Function ingestSwitchBlock

packages/compiler/src/template/pipeline/src/ingest.ts:676–737

* Ingest an `@switch` block into the given `ViewCompilation`.

(unit: ViewCompilationUnit, switchBlock: t.SwitchBlock)

 * Ingest an `@switch` block into the given `ViewCompilation`.
 */
function ingestSwitchBlock(unit: ViewCompilationUnit, switchBlock: t.SwitchBlock): void {
  // Don't ingest empty switches since they won't render anything.
  if (switchBlock.groups.length === 0) {
    return;
  }

  let firstXref: ir.XrefId | null = null;
  let conditions: Array<ir.ConditionalCaseExpr> = [];
  for (let i = 0; i < switchBlock.groups.length; i++) {
    const switchCaseGroup = switchBlock.groups[i];
    const cView = unit.job.allocateView(unit.xref);
    const tagName = ingestControlFlowInsertionPoint(unit, cView.xref, switchCaseGroup);
    let switchCaseI18nMeta: i18n.BlockPlaceholder | undefined = undefined;
    if (switchCaseGroup.i18n !== undefined) {
      if (!(switchCaseGroup.i18n instanceof i18n.BlockPlaceholder)) {
        throw Error(
          `Unhandled i18n metadata type for switch block: ${switchCaseGroup.i18n?.constructor.name}`,
        );
      }
      switchCaseI18nMeta = switchCaseGroup.i18n;
    }

    const createOp = i === 0 ? ir.createConditionalCreateOp : ir.createConditionalBranchCreateOp;

    const conditionalCreateOp = createOp(
      cView.xref,
      ir.TemplateKind.Block,
      tagName,
      'Case',
      ir.Namespace.HTML,
      switchCaseI18nMeta,
      switchCaseGroup.startSourceSpan,
      switchCaseGroup.sourceSpan,
    );
    unit.create.push(conditionalCreateOp);

    if (firstXref === null) {
      firstXref = cView.xref;
    }

    for (const switchCase of switchCaseGroup.cases) {
      const caseExpr = switchCase.expression
        ? convertAst(switchCase.expression, unit.job, switchBlock.startSourceSpan)
        : null;
      const conditionalCaseExpr = new ir.ConditionalCaseExpr(
        caseExpr,
        conditionalCreateOp.xref,
        conditionalCreateOp.handle,
      );
      conditions.push(conditionalCaseExpr);
    }
    ingestNodes(cView, switchCaseGroup.children);
  }
  unit.update.push(
    ir.createConditionalOp(
      firstXref!,
      convertAst(switchBlock.expression, unit.job, null),
      conditions,