🎭 ShowData

A debug node hiding in a QR pack

ShowData is the odd one out in ComfyUI-Simple_QR_Codes - a pack otherwise devoted to making QR codes, and this is a plain debugging utility. But it earns its place, because the pack's own workflow needs it: QRCodeReader returns decoded text as a list, and if you want to see that text in the UI instead of hunting through the console, you wire it into ShowData. It's the "look at what actually came out of this node" display that ComfyUI somehow still doesn't ship by default.

How it works

Two inputs: input (an any-type socket - it accepts whatever you connect, be it a string, number, list, or tensor) and data (a text widget). When the graph runs, ShowData renders input to a string and pushes it back into its own data widget over a websocket event (zentrocdot.data_updater.node_processed), so the text box updates live in the UI. It has no outputs - it's a terminal node whose whole job is to show you something.

It handles lists properly: one item prints as-is, multiple items print one per line. That's the detail that makes it the right companion for QRCodeReader, whose TEXT output is always a list - ShowData will display the decoded QR payload cleanly without you writing a list-extraction node.

What it's good for

• The QR verification loop: generator → stylize → QRCodeReader → ShowData. Type a URL into a QR node, run, and confirm the exact same URL comes back out. The pack's README explicitly frames this as the point - check the creation result within the same workflow.
• Generic debugging: wire any node's output into it to see what type and value you're actually dealing with. If a downstream node keeps rejecting your wire, ShowData tells you what's really on it.
• Keeping a value visible: as a display node it always runs and always shows its last-rendered value, which makes it a handy "sticky note" in a graph.

One honest limit: this is a text renderer, not a pretty printer. Feed it a big tensor and you'll get a wall of numbers you don't want. It shines on strings, numbers, and short lists - exactly the shapes a QR pipeline produces.

Installing it

Part of ComfyUI-Simple_QR_Codes: ComfyUI Manager → search "Simple QR Codes" → install → restart, or:

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

No model files, no special dependencies beyond the pack's normal set. It lives under QR Code Nodes → utils.