I made an (unofficial) Atom package for Observable notebooks! You can run and develop local notebooks, import notebooks from observablehq.com - all inside of Atom!
Download here: https://atom.io/packages/atom-observable
Once downloaded, while you are editing a “notebook” JS file, you can just press
Ctrl+Alt+O, and a new pane will appear with the rendered notebook. More usage can be found on the project repo
The main engine behind this package is an unofficial compiler for Observable syntax. That compiler can be found here - but, an explanatory notebook that goes more in-depth is here: https://observablehq.com/@asg017/an-unofficial-observablehq-compiler
Using this compiler, more people can use it to build VS Code extensions, web apps that use Observable syntax and the runtime, or even node.js powered notebooks in the terminal!
Let me know if you have any feedback/find bugs in the Atom package or unofficial compiler - and feel free to browse the Github repos and contribute!