code: function cleanData(originalData) {
              return originalData.reduce((acc, d) => {
                  d.value = +d[valueLabel];
                  d.key = String(d[nameLabel]);
  
                  return [...acc, d];
              }, []);
          }
docs: Cleaning data casting the values and keys to the proper type while keeping
  the rest of properties on the data
  @param  {StepChartData} originalData Data as provided on the container
  @private