docs: function i18nMapping(translation, elements, expressions, templateRoots, lastChildIndex) {
      var translationParts = translation.split(i18nTagRegex);
      var nbTemplates = templateRoots ? templateRoots.length + 1 : 1;
      var instructions = (new Array(nbTemplates)).fill(undefined);
      generateMappingInstructions(0, 0, translationParts, instructions, elements, expressions, templateRoots, lastChildIndex);
      return instructions;
  }