Hi @nagiek thanks for checking out visx.

Yes, the implementation of the data registry (whereby child components register their data in the parent chart context) with useEffect does prevent XYChart from being server-side rendered.

would propose moving the initial registerData call out of useEffect

There is no hook that is analogous to the legacy class component method componentWillMount. we could consider adding something a custom hook like the following as a workaround:

const useComponentWillMount = (cb) => {
    const willMount = useRef(true)
    if (willMount.current) cb()
    willMount.current = false
}

Thanks for quick response! Loving visx so far, especially XYChart. The reason I wanted it was because I wanted SVG for SSR charts, so I moved away from . My non-XYcharts work very well.

Hmm maybe that idea could work.. The DataProvider scales are only known after the render… would that imply using useComponentWillMount everywhere?

The other idea (might be a breaking change), would be to define all data upfront in the DataProvider, and have each Series component link into the dataRegistry via DataKey. This could be opt-in behaviour?