module.exports = {
  config: {
    type: 'doughnut',
    data: {
      labels: [0, 1, 2, 3, 4, 5],
      datasets: [
        {
          // option in dataset
          data: [0, 2, 4, null, 6, 8],
          borderColor: function(ctx) {
            var value = ctx.dataset.data[ctx.dataIndex] || 0;
            return value > 8 ? '#ff0000'
              : value > 6 ? '#00ff00'
              : value > 2 ? '#0000ff'
              : '#ff00ff';
          }
        },
        {
          // option in element (fallback)
          data: [0, 2, 4, null, 6, 8],
        }
      ]
    },
    options: {
      elements: {
        arc: {
          backgroundColor: 'transparent',
          borderColor: function(ctx) {
            var value = ctx.dataset.data[ctx.dataIndex] || 0;
            return value > 8 ? '#ff00ff'
              : value > 6 ? '#0000ff'
              : value > 2 ? '#ff0000'
              : '#00ff00';
          },
          borderWidth: 8
        }
      },
    }
  },
  options: {
    canvas: {
      height: 256,
      width: 512
    }
  }
};
