Draw horizontal line on chart in chart.js on v2

Question

I have drawn a line chart using chart.js. For the labels and datasets i am getting values from the database. I am new to chart.js and its very powerful library, yet i am una

Answer 1

Here's an example of getting it working in a Rails view if you're using it with the Chartkick gem:

<%=
  line_chart profit_per_day_chart_path(staff), xtitle: 'Day', ytitle: 'Profit',
    library: {
      annotation: {
        annotations: [
          {
            type: 'line',
            mode: 'horizontal',
            scaleID: 'y-axis-0',
            value: 20,
            label: {
              content: 'My Horizontal Line',
              enabled: true
            }
          }
        ]
      }
    }
%>

Ensure that you've registered the chartjs-plugin-annotation.js plugin with Chart.js first:

import ChartAnnotationsPlugin from 'chartjs-plugin-annotation';
Chart.plugins.register(ChartAnnotationsPlugin);