text: export default function(array, f) {
    var i = -1,
        n = array.length,
        a,
        b,
        c;
  
    if (arguments.length === 1) {
      while (++i < n) if ((b = array[i]) != null && b >= b) { a = c = b; break; }
      while (++i < n) if ((b = array[i]) != null) {
        if (a > b) a = b;
        if (c < b) c = b;
      }
    }
  
    else {
      while (++i < n) if ((b = f(array[i], i, array)) != null && b >= b) { a = c = b; break; }
      while (++i < n) if ((b = f(array[i], i, array)) != null) {
        if (a > b) a = b;
        if (c < b) c = b;
      }
    }
  
    return [a, c];
  };
  