Restore a flattened structure to a hash

rehash.js

// I use this to reconstitute the values returned by HGETALL ( http://redis.io/commands/hgetall ).

function rehash (values) {
  var hash = {}
    , isKey = true
    , key;
  if (!Array.isArray(values)) return hash;
  values.forEach(function(value) {
    if (isKey) {
      key = value;
      hash[key] = null;
    } else {
      hash[key] = value;
    }
    isKey = !isKey;
  });
  return hash;
}

The docs for hgetall suggest the list will be contiguous so it should be fine?

Nice.

You can write it using a reduce without any intermediate state:

function rehash (xs) {
    if (!Array.isArray(xs)) return {}
    else return xs.reduce(function (acc, x, i) {
        if (i % 2 == 0) acc[x] = xs[i+1]
        return acc;
    }, {})
}
console.dir(rehash([ 'a', 1, 'b', 2, 'c', 3 ]));

{ a: 1, b: 2, c: 3 }

Thanks, @substack. That's delightful. You going to office hours tomorrow?

Thats pretty nice, but my noddy test I was using suggests that its still slower than my option ?

https://gist.github.com/1110433