# Basic

const config = {
  type: 'doughnut',
  data,
  options: {
    aspectRatio: 2,
    plugins: {
      annotation: {
        annotations: {
          annotation
        }
      }
    }
  }
};

const annotation = {
  type: 'doughnutLabel',
  content: ({chart}) => ['Average',
    average(chart).toFixed(2),
    'on last ' + chart.data.labels.length + ' months'
  ],
  font: [{size: 60}, {size: 50}, {size: 30}],
  color: ['black', 'red', 'grey']
};

function average(chart) {
  const values = chart.data.datasets[0].data;
  return values.reduce((a, b) => a + b, 0) / values.length;
}

const DATA_COUNT = 12;
const MIN = 0;
const MAX = 100;

const numberCfg = {count: DATA_COUNT, min: MIN, max: MAX, decimals: 0};

const data = {
  labels: ['January', 'February', 'March', 'April', 'May', 'June', 'July', 'August', 'September', 'October', 'November', 'December'],
  datasets: [{
    data: Utils.numbers(numberCfg)
  }]
};