code: function toUniqueStrings(input) {
    const list = (Array.isArray(input) ? input : [input])
      .map(el => (typeof el === 'string' ? el.trim() : null))
      .filter(Boolean)
    return list.length > 1 ? Array.from(new Set(list)) : list
  }
docs: Return an array of unique trimmed strings,
  from input which can be a string or an array of strings
  @param {Array|string} input
  @return {string[]}