Add a hours:minutes:seconds ETA

[cmizzi]

For work projects, I need to use a progress bar with nodeJS and, I think that is could be cool to have a hours, minutes and seconds ETA for long download.

[callumlocke]

+1

[hallas]

@jdan Can you take a look?

[jdan]

Heya @cmizzi, thanks for the PR.

To be perfectly honest I'm not sure how I feel adding more tokens. I think a better solution might be to just allow users to pass in their own token formatters.

var bar = new ProgressBar('  downloading [:bar] :percent :etas', {
    complete: '=',
    incomplete: ' ',
    width: 20,
    total: len,
    tokens: {
      // maybe not `eta` here specifically...
      ':hour': function(eta) {
        return ...
      }
    }
  });

Thoughts?

[cmizzi]

It could be a good job but it makes user recreate a child module if they don't want specify each time custom tokens.

[lbeschastny]

@jdan totally agree with you about keeping the number of tokens small.

Though, it'll be nice for node-progress to pretty-print :eta either by some flag, or by default (something like #75).