Learn TypeScript 3 by Building Web Applications

Implementing the renderChart method

Finally, let's now implement the most important piece of our puzzle, the renderChart method. We will code it together piece by piece as follows:

1. First of all, we need to retrieve the selections made by the user in the chart form. We can do so using the view's getChartFormDetails method:

console.log("Rendering the chart"); 
const chartFormDetails = this._view.getChartFormDetails(); 

Of course, we need to make sure that there are no errors:

if (chartFormDetails.error) { 
    console.error("Failed to retrieve the chart details",      chartFormDetails.error); 
    return; 
} 

2. Furthermore, we can also verify that all the properties that we expected are defined and available:

if (!chartFormDetails.countryId || !chartFormDetails.indicator ...