code: function getSourceRepeatingSections(rule) {
      return _.chain(rule.ruleConditionalStatements)
        .map(function(ruleConditionalStatement) {
          var sourceId = ruleConditionalStatement.sourceField.toString();
          return fieldSectionMapping[sourceId];
        })
        .filter(function(section) {
          return section && section.repeating;
        })
        .map(function(repeatingSection) {
          return repeatingSection._id.toString();
        })
        .uniq()
        .value();
    }
docs: Get ids of repeating sections with fields which act as sources in a rule
  @param rule
  @returns {String[]}