d4 is an experiment in using React to produce data-driven documents (ala d3) that are performant and understandable. This is not a library, but rather a demonstration that it's possible (and preferable) to use React instead of the core of d3. d3 can produce fantastic results. Look no further than Mike Bostock's blocks for examples. Unfortunately, I always find d3 code surprisingly difficult to understand and extend, in the same way I used to find code difficult to approach before React encouraged a declarative style. By using React (which can render SVGs, no problem) for data-driven documents, we can improve comprehension and performance and use tools from the React ecosystem.