PlotlyJS: how to introduce shapes into time series?

General Usage
4

Sorry for one aside topic. Do you know how can I pass the following information available in the plotylyjs documentation into PlotlyJS:

textfont: {
    family: 'sans serif',
    size: 18,
    color: '#ff7f0e'
  },

I tried this, but it does not work (with many variations on the empty space in “sans serif”)::

textfont = [family = "sans serif",  size = 18, color = "#ff7f0e"],

For the issue above, the size of the textfont is not relevant. But sometimes, I need a larger font, and I do not know if it is possible to insert it into PlotlyJS.

Thanks.