Sankey diagram - why being forced to use indexes for `source` and `target` properties in link?

[comatory]

In your docs for links array you mention:

An array of objects matching the following shape, where both source and target are the indexes of the nodes they intent to represent

This means that for JSON-like structures, it can get quite difficult to get the ordering of links right. I see that the library is using d3-sankey as one of its dependencies. Their docs mention that using string for id is possible and then source and targetcan refer to that ID. Would it be possible to add this feature as well?