Reversing a string using .from

I was rather hoping that this series would finish with .some but here we are again reversing a string. This time, we're using Array.from().

This is the ES6 version

const Bruce_ArrayFrom = (str, buf = []) => {
  Array.from(str, (itm) =>
    buf.unshift(itm)
  );
  return buf.join("");
}

and the ES3 version, thanks to Babel

var Bruce_ArrayFromES3 = function Bruce_ArrayFromES3(str) {
  var buf =
    arguments.length > 1 && arguments[1] !== undefined ? arguments[1] : [];
  Array.from(str, function(itm) {
    return buf.unshift(itm);
  });
  return buf.join("");
};

In terms of speed, both are awful, both sitting down the bottom of the list. Only the RegExp version is slower. Intriguingly, the ES3 version is slower than the ES6 (for reasons unknown.)

Hopefully, that's the end of reversing strings with JavaScript. Like Perl, there's more than one way to do it though some ways are better than others.

Comments

[Adam Crockett 🌀]

Is there not an reverse method on the string prototype, there is on the array prototype.

[Bruce Axtens]

As it turns out, no, there is no String.prototype.reverse(). For ages therefore people have been using (usually) var reversedString = "string".split("").reverse().join("") and other approaches.

My 'series' (for want of a better word) came out of Sarah Chima's original posting discussing the issue and offering some options.

[Adam Crockett 🌀]

In that case, nice! Good to measure perf as well nice touch.

[Bruce Axtens]

Thank you.