Switch Chain (Drawer)

Sometimes you want a switch with no toggle: a row of optional upstream branches, and whichever one actually produced a value wins, in priority order. That's DrawerSwitchChain - up to 64 inputs, one output, and the rule is simple: the last connected non-empty value wins.

It's the sibling of DrawerSwitch in ComfyUI-Drawer, Kuroi's mobile-friendly drawer platform. Where DrawerSwitch is an A/B valve you flip, SwitchChain is a fallback ladder you wire and forget. There's no selector, nothing to click - the graph decides by which branches are live.

The mechanism

Inputs are value_1 through value_64, all optional, all typed * (any type). The node scans them from the highest number down - so value_64 has top priority - and returns the first one that is connected and non-empty. A string counts as empty if it's blank after stripping whitespace; other types just need to be present. If everything is empty or nothing is connected, it outputs None.

Here's the subtle part that's easy to trip on: this isn't "first non-empty wins" in the rgthree Any Switch sense - it's last wins, because scanning starts at the top of the numbering. If you only use value_1 and value_2, then value_2 wins whenever it has content, and value_1 is the fallback. That's intentional: it preserves the old A/B-switch meaning where the second input overrides the first. If you want something to be a higher-priority override, wire it into a higher-numbered slot.

A None output is a feature, not a bug - per the standard ComfyUI plumbing pattern, a deliberately-empty output feeding an optional input is exactly how you mute a branch from inside the data instead of bypassing nodes.

Installing it

cd ComfyUI/custom_nodes
git clone https://github.com/Kuroi961/ComfyUI-Drawer.git
pip install -r ComfyUI-Drawer/requirements.txt

Or search ComfyUI-Drawer in ComfyUI Manager. requirements.txt is just Send2Trash; no models, no extra system tools for the node itself.

Gotchas

• Last non-empty wins, not first. This is the #1 confusion. Think "highest-numbered connected input that has a value", and wire priority accordingly.
• Blank strings are skipped, so an upstream that outputs an empty prompt cleanly falls through to the next candidate. That's usually what you want.
• It's a plain * node, so ComfyUI won't type-check the sockets - if you mix types (an IMAGE on value_3, a model on value_5), the node will happily return whichever wins and hand it downstream, where it may fail. Keep one type per chain.
• If all inputs are empty you get None, which some downstream nodes reject and some treat as "unconnected". If a consumer chokes, that's the cause.

For workflows with several optional branches - "use the upscaled pass if it exists, otherwise the raw one, otherwise the placeholder" - this is a tidy single-node answer. Just remember which end of the chain has the authority.