In my project, I have a class called Chart that has various subclasses like BarChart and TimeseriesChart, all of which extend the base Chart class.
To create these charts, I use a method named buildChart. This method uses an enum called ChartsEnum (examples include stackedTimeseries and barChart) to map the correct class using a Map:
export function buildChart(type: Charts, data: Array<TimeseriesData>) {
var chartsMap = new Map<Charts, InstantiableAbstractClass<typeof Chart>([
[Charts.stackedTimeseries, TimeseriesChart],
[Charts.barChart, BarChart],
])
const chart = chartsMap.get(type)
return new chart(data).chart;
}
The definition for the type InstantiableAbstractClass is as follows:
export declare type InstantiableClass<T> = (new ( ...args: any) => { [x: string]: any }) & T;
For instance, the constructor of the TimeseriesChart class looks like this:
export class TimeseriesChart extends Chart{
constructor(data: Array<TimeseriesData>) {
super(data);
}
}
Now, the goal is to add a new attribute called options to the chart class alongside the existing data attribute. The issue arises because different types of options are required for each ChartType (BarChart, TimeseriesChart). For example, BarChart needs these properties:
{
start: number;
end?: number;
}
while TimeseriesChart requires something like this:
{
description: string;
}
If we update the constructor of TimeseriesChart with options, it would look like this:
export class TimeseriesChart extends Chart{
constructor(data: Array<TimeseriesData>, options: TimeseriesChartOptions) {
super(data, options);
}
}
This necessitates adding a new argument options to the buildChart method, which can then be passed to specific classes (similar to how we pass the data argument).
What would be the best approach to handle this situation? One possibility could be utilizing generics and defining different types for options based on the subclasses, but adjusting the InstantiableAbstractClass type accordingly presents a challenge.
You can explore a complete example with additional explanations here.
Your guidance and insights are highly appreciated! Feel free to request more information if needed.
Thank you and best regards, Lukas