code: function pair(name, value, i) {
    if(typeof name === 'function') return name(value);
    if(!name) return {name: `notMappedField${i}`, value};
  
    var candidateKey = name.split('|');
    var directive = candidateKey[1];
    if(keys.indexOf(directive) !== -1) return {name: candidateKey[0], value: format[directive](value)};
  
    return {name, value};
  }
docs: /* Generate a proper key / value pair
  @param {string|function} key