docs: function collapse(values) {
    if (!values || !values.length) return [];
    var length = values.length;
  
    // Truncate values
    var replica = [];
    for (var i = length; i--;) {
      var sample = strip(values[i]);
      if (!+sample) replica[i] = '0';
      else replica[i] = truncate(values[i]);
    }
  
    // Collapse values
    var a = replica[0], b = replica[1], c = replica[2], d = replica[3];
    switch (length) {
      case 2: if (a === b) return [a];
      case 3: {
        if (a === b && b === c) return [a];
        if (a === c) return [a, b];
      }
      case 4: {
        if (a === b && b === c && c === d) return [a];
        if (a === c && b === d) return [a, b];
        if (b === d) return [a, b, c];
      }
      default: return values;
    }
  }