If you just want to render something and don't need layout, this could be very small. I guess, d3 might be one of the more popular options. At work I'm working

If you just want to render something and don't need layout, this could be very small. I guess, d3 might be one of the more popular options. At work I'm working on a graph drawing library and we have quite a bit more layout code; heck, for a hierarchical layout (akin to dot) you'd need about 4 or 5 MiB (no idea how well it gzips right now, though) of JS. Good layout algorithms can be complex, and thus large.