Allow for nested objects as data/keys

Firstly, thanks so much for this lib. It’s really useful for a project I’m currently working on and the code is really easy to follow. Awesome work! 🙌

For my project I’m using nested data objects that I pass to the format method. Right now I have to flatten the object for it to work, for example this:

var data = {
  'user': 'Steve',
  'members': {
    'count': 10
  }
};

becomes:

var data = {
  'user': 'Steve',
  'members.count': 10
};

This works fine but when the data object is huge, with lots of nested data we don’t care about, it becomes a bit of a performance issue.

A work around for this would be to update the interpretSimple function to be:

function interpretSimple (id) {
  return function format (args) {
    var parts = id.split('.');
    if (parts.length > 1) {
      var i = 0;
      var l = parts.length;
      var a = args;
      for (i; i < l; i++) {
        a = a[parts[i]];
        if (!a) return '' + args[id];
      }
      return '' + a;
    }
    return '' + args[id];
  }
}

This would look for nested variables in an object but would fallback to how things currently work, so would be a minor update / backwards compatible.

Is this something that could be consider? If yes I can put together a PR today along with updated unit tests etc.

[minimalmonkey]

Awesome, thanks for the direction. Will take a look at this before making a PR.

[zdfs]

Thank you so much, Andy. This really helps us a lot.