code: function numericField (ops) {
    const calculateScore = (x, i, resultset) => {
      x.score = +x.match.filter(
        item => item.startsWith(ops.fieldName)
      )[0].split(':')[1];
      return x
    };
    return ops
      .resultSet
      .map(calculateScore)
    // sort by score descending
      .sort(ops.sort)
    // limit to n hits
      .slice(ops.offset, ops.limit)
  }
docs: TODO: put in some defaults