Documentation: Prefer (chartInstance) on init

[wjaspers]

When using the [chartCallback] to store a reference to the newly created chart, it is called again during export. This can be confusing if your chart is updated dynamically, as the original chart reference will be reassigned.

[karolkolodziej]

Hi @wjaspers! Thank you for the feedback.
The chart callback is triggered on export regardless using highcharts-anuglar- see demo.

This isn't properly documented but the best way to get the chart instance reference is by the Output:

highcharts-angular/highcharts-angular/src/lib/highcharts-chart.component.ts

Line 20 in b4751e5

@Output() chartInstance = new EventEmitter<Highcharts.Chart | null>(); // #26

Let's treat this as a documentation improvement task.