Q:

Aurelia + Kendo - How can I reload a Kendo pie chart after changing data?

I'm attempting to use Aurelia and the Kendo UI Bridge to display data in a pie chart. Due to project requirements, I've got the pie chart widget loading in a custom element. If my data is available before the page loads, everything works fine.
View Model
export class PieChartCustomElement {
    chartData = [];
    chartSeries = [{
        type: 'pie',
        startAngle: 150,
        field: 'percent',
        categoryField: 'languageName'
    }];
    // other variables

    constructor() {
        //if I hard-code the data here, all works fine
        this.chartData = [
            { languageName: 'English', percent: 62.5 },
            { languageName: 'Spanish', percent: 35 },
            { languageName: 'Esperanto', percent: 2.5 }
        ];
    }
}

View
<template>
  <require from="aurelia-kendoui-bridge/chart/chart"></require>
  <h4>pie chart custom element</h4>
  <ak-chart k-title.bind="title"
    k-legend.bind="legend"
    k-series-defaults.bind="chartDefaults"
    k-series.bind="chartSeries"
    k-data-source.bind="chartData"
    k-tooltip.bind="tooltip"
    k-widget.bind="pieChart"></ak-chart>  
</template>

In reality, my data is fetched from a REST API using a promise, so I don't have the data when the page initially loads. Further, I need to pass a parameter to the REST API that comes in via a @bindable attribute on the element, so I cannot populate my data source in the constructor. Hence, something like this:
@bindable({ defaultBindingMode: bindingMode.oneWay }) someArg;

attached() {
    // 'api' is injected and is a simple JS class that calls the REST API
    this.api.getChartData(this.someArg).then((results) => {
        this.chartData = results;
    });
}

I'm pretty sure that this is due to the fact that the pie chart widget has already loaded and does not automatically reload when its backing data is changed. If this is actually the case, how do I get the pie chart to reload when I change its data set? If its not, what am I doing wrong?
Working Gist - Comment/uncomment code in the constructor/activate events as indicated to see the behavior.

A:

I believe the method you are looking for is the setDataSource() 
In pie-chart.js in the attached() method in your Gist try changing
this.chartData = languageData;

to
this.pieChart.setDataSource(this.chartData);

