Sum method not giving correct result

[NeeruAR]

I am trying to use the aggregate sum method in echart but it is not giving proper result.
For the month of Mar output should be 1000, for April 210 and for August 148.

$.when(
  $.getScript(
    'https://fastly.jsdelivr.net/npm/echarts-simple-transform/dist/ecSimpleTransform.min.js'  )
).done(function (res) {
  run(res);
});

function run() {
  echarts.registerTransform(ecSimpleTransform.aggregate);
  option = {
	    dataset: [
	      {
	        id: 'raw',
	        dimensions: ['billAmount', 'billMonth'],
	        source: [
          {
            billMonth: 'Mar',
            billAmount: '400'
          },
          {
            billMonth: 'Mar',
            billAmount: '100'
          },
          {
            billMonth: 'Mar',
            billAmount: '500'
          },
          {
            billMonth: 'April',
            billAmount: '10'
          },
          {
            billMonth: 'April',
            billAmount: '200'
          },
          {
            billMonth: 'August',
            billAmount: '148'
          }
        ]
      },
      {
        id: 'month',
        fromDatasetId: 'raw',
        transform: [
          {
            type: 'filter',
            config: {
              dimension: 'billMonth',
              eq: 'Mar'
            }
          }
        ]
      },
      {
	       id: 'bill_sum',
        fromDatasetId: 'raw',
        transform: [
          {
            type: 'ecSimpleTransform:aggregate',
            config: {
              resultDimensions: [
                { from: 'billAmount', method: 'sum' },
                { from: 'billMonth' }
              ],
              groupBy: 'billMonth'
            }
          }
        ]
      },
   ],
    title: {
      text: 'SUM OF BILL'
    },
    tooltip: {
      trigger: 'axis',
      confine: true
    },
    xAxis: {
      name: 'billMonth',
      nameLocation: 'middle',
      nameGap: 30,
      scale: true,
      type: 'category',
      boundaryGap: true,
      axisLabel: {
        interval: 0,
        fontSize: 12,
        rotate: 15
      }
    },
    yAxis: {
      type: 'value',
      axisLabel: {
        interval: 0,
        fontSize: 12,
        rotate: 7
      }
    },
    grid: {
      bottom: 100
    },
    legend: {
      width: 330,
      type: 'scroll'
    },
    series: [
      {
        type: 'bar',
        datasetId: 'bill_sum',
        name: 'billamount',
        encode: {
          x: 'billMonth',
          y: 'billAmount'
        },
        color: 'red'
      }
    ] 
   };
    myChart.setOption(option);
}

Error Output :

[svedova]

In my case it always skips the first row.

[helgasoft]

duplicate of #1

[namannitr]

Two stacked bugs produced the wrong monthly totals:

1. Published dist still initialized SUM to 0, so the first row of each group was dropped (August → 0; April 10+200 → 200; Mar 400+100+500 → 600). Same root cause as initial value of sum should be the first value instead of 0 #1.
2. billAmount values are strings ('400'). JS + then concatenates instead of adding.

PR #9 rebuilds dist and coerces arithmetic cells with Number(...). The fixture from this issue now yields Mar 1000, April 210, August 148.