Usage:
    gettextjs [-i] [-v] [--js] <locale-path> [<out-dir>]

Options:
    -h --help       Show this screen.
    --version       Show version.
    -i --indent     Indent JSON file.
    -v --verbose    Print stuff while doing work.
    --js            Compile to JS instead of JSON.

Gettext.load('/base/url/to/locale', 'en', 'messages').then(function(gettext){
    var msgstr = gettext.gettext('msgid');
});

var gettext = new Gettext(EN_MESSAGES);
var msgstr = gettext.gettext('msgid');