Is it possible to have V3 and V4 coexisting in a project? Like, adding some of the awesome v4 new things to an already working v3 project without having to rework all the v3 code to v4 compliance?
I've tried doing this with v4 beta, with strange behaviours :)
Hmm. It might be possible, though it doesn’t sound like a great idea to have both D3 3.x and the D3 4.0 default bundle loaded simultaneously, since there will be a lot of overlap. A better strategy might be to load just the new modules you want to use. Like if you just want the new force layout, then load d3-force: https://github.com/d3/d3-force
But it might be best to just migrate to 4.0. I know the changelist is long, but it might not be as hard as you think to migrate. And you can always send your questions to the d3-js Google group or d3.js on Stack Overflow and I’ll try to help.