widget lifecycle methods / accessing the div after it has been mounted

👋 hello from plotly! we’re working on the next version of the Plotly Jupyter widget in https://github.com/plotly/plotly.py/pull/942

There are some methods in our JS library that require a mounted/attached div (e.g. to know the size of the mounted div). However, in the widgets render method, we only have access to the unmounted/unattached div.

Are there any component lifecycle methods or events that we can utilize to customize the behaviour of the widget after it has been mounted on the DOM? To start, we would use this behaviour to either resize our plot to fill the container or defer making the plot until the div has been attached.

Many thanks!

(cc @jmmease)

[jonmmease]

For some reason the after-show event, referenced by ipyleaflet in the code snippet above, wasn’t being triggered for me. But when I dumped out all of the events I got a before-attach event followed by an after-attach event. And the after-attach event is exactly what we needed.

Thanks!

[chriddyp]

Many thanks everyone 🙇