formatter keyword support

[bigbes]

You have no formatter argument support in TooltipConfig, and it seems to me that embedding JS code into python JSON won't be the easiest thing to do..

e.g.

        tooltip: {
            formatter: function() {
                var s = '<b>'+ Highcharts.dateFormat('%A, %b %e, %Y', this.x) +'</b>';
                $.each(this.points, function(i, point) {
                    s += '<br/>1 USD = '+ point.y +' EUR';
                });

                return s;
            }
        },

which we can't do, because of we can't print string (function) without quotes.

'<b>'+ Highcharts.dateFormat('%A, %b %e, %Y', this.x) +'</b>';
                $.each(this.points, function(i, point) {
                    s += '<br/>1 USD = '+ point.y +' EUR';
                });

What can we do with it?
I'm sorry for my poor English.

[bigbes]

It comes to me, that we can do such things as recreating value:

if (config.tooltip && config.tooltip.formatter){
    config.tooltip.formatter = Function(config.tooltip.formatter);
}

from JS script.