function typeReferenceToExpression()

in src/decorator_downlevel_transformer.ts [256:291]
34 lines of code
16 McCabe index (conditional complexity)

function typeReferenceToExpression(
    entityNameToExpression: (n: ts.EntityName) => ts.Expression | undefined,
    node: ts.TypeNode): ts.Expression|undefined {
  let kind = node.kind;
  if (ts.isLiteralTypeNode(node)) {
    // Treat literal types like their base type (boolean, string, number).
    kind = node.literal.kind;
  }
  switch (kind) {
    case ts.SyntaxKind.FunctionType:
    case ts.SyntaxKind.ConstructorType:
      return ts.factory.createIdentifier('Function');
    case ts.SyntaxKind.ArrayType:
    case ts.SyntaxKind.TupleType:
      return ts.factory.createIdentifier('Array');
    case ts.SyntaxKind.TypePredicate:
    case ts.SyntaxKind.TrueKeyword:
    case ts.SyntaxKind.FalseKeyword:
    case ts.SyntaxKind.BooleanKeyword:
      return ts.factory.createIdentifier('Boolean');
    case ts.SyntaxKind.StringLiteral:
    case ts.SyntaxKind.StringKeyword:
      return ts.factory.createIdentifier('String');
    case ts.SyntaxKind.ObjectKeyword:
      return ts.factory.createIdentifier('Object');
    case ts.SyntaxKind.NumberKeyword:
    case ts.SyntaxKind.NumericLiteral:
      return ts.factory.createIdentifier('Number');
    case ts.SyntaxKind.TypeReference:
      const typeRef = node as ts.TypeReferenceNode;
      // Ignore any generic types, just return the base type.
      return entityNameToExpression(typeRef.typeName);
    default:
      return undefined;
  }
}