 Object Notation (JSON) specification that plotly.js uses to represent, serialize, and render web graphics. A lot of documentation you’ll find online about plotly (e.g., the online <a href="https://plot.ly/r/reference/">figure reference</a>) implicitly refers to this JSON specification, so it can helpful to know how to “work backwards” from that documentation (i.e., translate JSON into to R code). If you’d like to learn details about mapping between R and JSON, Chapter <a href="json.html#json">19</a