Fast Node Bypasser (legacy)

If you're landing here, odds are you searched for a node called "Fast Node Bypasser" and got a result with "(legacy)" tacked on the end. Don't worry - you found the right thing. This is the bypasser; the "(legacy)" label just means your workflow was saved before MoonPack v0.2 renamed all its registry keys to a MoonPack_ prefix. The full writeup lives on the MoonPack_FastNodeBypasser page, and this one explains the rename and what it means for you.

What it does

It's a virtual control node that puts a bypass toggle on every node connected to it - or, if you set the matchTitle property to a regex like ^KSampler, on every node whose title matches. Wire your four KSamplers into it, and suddenly you have a little control panel where one click mutes a branch. Right-click for Bypass All / Enable All / Toggle All / Refresh. There are no inputs or outputs on the schema and no server-side execution; all the behavior lives in the frontend, which is why toggling feels instant.

The rename, and why you should care

MoonPack v0.1 registered this node under the plain key FastNodeBypasser. v0.2 moved everything to MoonPack_FastNodeBypasser so the whole pack shares a consistent prefix. To keep old workflows loadable, the pack keeps the old key registered as an alias - that's the "(legacy)" you see in the Add Node menu, and it's also why a workflow you saved months ago still opens today.

The catch: aliases have a shelf life. The README says legacy keys are kept "for one release cycle" and removed in 1.0. If you load an old workflow, save it once after loading - ComfyUI writes the workflow back with the new MoonPack_FastNodeBypasser key, and you're migrated. If you never re-save, the day the alias goes away is the day that workflow stops loading cleanly.

Installing it

It installs with the whole pack, either way you get it:

cd ComfyUI/custom_nodes
git clone https://github.com/moonwhaler/comfyui-moonpack.git

…or via ComfyUI Manager, searching MoonPack. Restart ComfyUI, and the node appears under MoonPack/utils. No model downloads, no heavy dependencies - the pack has no third-party Python requirements beyond what ComfyUI already ships.

Bottom line

The legacy label is a red herring. Whether your workflow says FastNodeBypasser or MoonPack_FastNodeBypasser, it's the same fast, client-side, no-groups-required bypasser. Just do the one-save migration now so a future update doesn't leave you with a broken graph.