MultiSeries code example error on flat()

[Tii]

I'm trying to make a multi-series chart like the example here: https://www.chartjs.org/docs/latest/samples/other-charts/multi-series-pie.html

problem is on this line :

            datasetColors = datasetColors.flat();

Property 'flat' does not exist on type '(string | ((ctx: ScriptableContext<"doughnut">, options: AnyObject) => Color) | _DeepPartialObject | ... 5 more ... | ((ctx: ScriptableContext<...>, options: AnyObject) => Color))[]'. Do you need to change your target library? Try changing the lib compiler option to 'es2019' or later.
[ng] 61 datasetColors = datasetColors.flat();

It seems like the backgroundColor is typed as a Color which is a String so the flat() function does not apply.

how can I fix this ?

[kurkle]

The datasetColors is an array created in the lines above, so it has flat().
The compler error suggests the right fix:

Try changing the lib compiler option to 'es2019' or later.

The array.flat() was introduced in es2019.

[Tii]

thank you, I changed es2018 to es2019 in the tsconfig.json and it fixed my issue !