code: function normalizeFields(input) {
    if (!input) return;
    if (!Array.isArray(input)) input = [ input ];
  
    return flatten(input).filter(Boolean).map(normalizeField);
  }
docs: Takes the `input` fields value and normalizes it into a single array.
  
  @param {Mixed} input  The links value to normalize.
  @return {Array}