code: function expand(tokens) {
    for (let i = 0, l = tokens.length; i < l; i++) {
      if (tokens[i].length > 1)
        tokens[i] = [tokens[i], tokens[i][0]];
    }
  
    return tokens;
  }
docs: TODO: option for full initials? (else if solution involves only abbrev, we skip) TODO: disallow single token (on option) TODO: option to skip or not TODO: possibility to pass tokens rather than a string TODO: tweak power set token number threshold (heuristic function genre n or n - 1 etc.) TODO: option to convert to acronym or not TODO: predicate to know if we acronym or not (like do it only on firstName for instance) TODO: return sets as strings, not tokens 
  Function expanding token by multiplexing tokens that are not initials.
  
  @param  {array} tokens - List of tokens.
  @param  {array}