code: function getJSONAccessor(propValue, configuration) {
    if (propValue === '-') {
      return object => object;
    }
    if (typeof propValue === 'string') {
      return object => {
        return get(object, propValue);
      };
    }
    return propValue;
  }
docs: Calculates an accessor function from a JSON string '-' : x => x 'a.b.c': x => x.a.b.c