Adding extra information to dygraph legend?

Question

Is there an easy way to be able to add extra data to the dygraph legend?

I obviously want to display the x & y data values, but the underlying data point holds extra information that I want to show to the user.

I can obviously use the callback option to find out what point has been moused over . So is the only option to use the callback and then have my own div which shows this information rather than using the dygraph legend?

Answer 1

The easiest way to do this is with the legendFormatter option in the upcoming 2.0.0 release:

function legendFormatter(data) {
  if (data.x == null) return '';  // no selection
  return data.xHTML +
      data.series
      .map(v => v.labelHTML + ': ' + v.yHTML)  // modify as needed
      .join(' ');
}

new Dygraph(div, data, { legendFormatter });