Function ingestIfBlock

packages/compiler/src/template/pipeline/src/ingest.ts:506–555

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

(unit: ViewCompilationUnit, ifBlock: t.IfBlock)

 * Ingest an `@if` block into the given `ViewCompilation`.
 */
function ingestIfBlock(unit: ViewCompilationUnit, ifBlock: t.IfBlock): void {
  let firstXref: ir.XrefId | null = null;
  let conditions: Array<ir.ConditionalCaseExpr> = [];
  for (let i = 0; i < ifBlock.branches.length; i++) {
    const ifCase = ifBlock.branches[i];
    const cView = unit.job.allocateView(unit.xref);
    const tagName = ingestControlFlowInsertionPoint(unit, cView.xref, ifCase);

    if (ifCase.expressionAlias !== null) {
      cView.contextVariables.set(ifCase.expressionAlias.name, ir.CTX_REF);
    }

    let ifCaseI18nMeta: i18n.BlockPlaceholder | undefined = undefined;
    if (ifCase.i18n !== undefined) {
      if (!(ifCase.i18n instanceof i18n.BlockPlaceholder)) {
        throw Error(`Unhandled i18n metadata type for if block: ${ifCase.i18n?.constructor.name}`);
      }
      ifCaseI18nMeta = ifCase.i18n;
    }

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

    const conditionalCreateOp = createOp(
      cView.xref,
      ir.TemplateKind.Block,
      tagName,
      'Conditional',
      ir.Namespace.HTML,
      ifCaseI18nMeta,
      ifCase.startSourceSpan,
      ifCase.sourceSpan,
    );
    unit.create.push(conditionalCreateOp);

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

    const caseExpr = ifCase.expression ? convertAst(ifCase.expression, unit.job, null) : null;
    const conditionalCaseExpr = new ir.ConditionalCaseExpr(
      caseExpr,
      conditionalCreateOp.xref,
      conditionalCreateOp.handle,
      ifCase.expressionAlias,
    );
    conditions.push(conditionalCaseExpr);
    ingestNodes(cView, ifCase.children);
  }
  unit.update.push(ir.createConditionalOp(firstXref!, null, conditions, ifBlock.sourceSpan));
}

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