Function parseTemplate

packages/compiler/src/render3/view/template.ts:140–276

(
  template: string,
  templateUrl: string,
  options: ParseTemplateOptions = {},
)

 * @param options options to modify how the template is parsed
 */
export function parseTemplate(
  template: string,
  templateUrl: string,
  options: ParseTemplateOptions = {},
): ParsedTemplate {
  const {preserveWhitespaces, enableI18nLegacyMessageIdFormat} = options;
  const selectorlessEnabled = options.enableSelectorless ?? false;
  const bindingParser = makeBindingParser(selectorlessEnabled);
  const htmlParser = new HtmlParser();
  const parseResult = htmlParser.parse(template, templateUrl, {
    leadingTriviaChars: LEADING_TRIVIA_CHARS,
    ...options,
    tokenizeExpansionForms: true,
    tokenizeBlocks: options.enableBlockSyntax ?? true,
    tokenizeLet: options.enableLetSyntax ?? true,
    selectorlessEnabled,
  });

  if (
    !options.alwaysAttemptHtmlToR3AstConversion &&
    parseResult.errors &&
    parseResult.errors.length > 0
  ) {
    const parsedTemplate: ParsedTemplate = {
      preserveWhitespaces,
      errors: parseResult.errors,
      nodes: [],
      styleUrls: [],
      styles: [],
      ngContentSelectors: [],
    };
    if (options.collectCommentNodes) {
      parsedTemplate.commentNodes = [];
    }
    return parsedTemplate;
  }

  let rootNodes: html.Node[] = parseResult.rootNodes;

  // We need to use the same `retainEmptyTokens` value for both parses to avoid
  // causing a mismatch when reusing source spans, even if the
  // `preserveSignificantWhitespace` behavior is different between the two
  // parses.
  const retainEmptyTokens = !(options.preserveSignificantWhitespace ?? true);

  // process i18n meta information (scan attributes, generate ids)
  // before we run whitespace removal process, because existing i18n
  // extraction process (ng extract-i18n) relies on a raw content to generate
  // message ids
  const i18nMetaVisitor = new I18nMetaVisitor(
    /* keepI18nAttrs */ !preserveWhitespaces,
    enableI18nLegacyMessageIdFormat,
    options.preserveSignificantWhitespace,
    retainEmptyTokens,
  );
  const i18nMetaResult = i18nMetaVisitor.visitAllWithErrors(rootNodes);

  if (