_.join

You've got a list of tags, filenames, or prompt fragments and you want one clean string out of it. That's _.join: the JavaScript Array.join brought to Comfy, where every element gets coerced to text and glued together with a separator you choose. Simple, and surprisingly easy to reach for once you're juggling lists.

What it is

One node in the ovum/underscore family inside sfinktah/comfy-ovum, wrapping the join method of underscore3, a Python port of Underscore.js. The implementation is a one-liner: glue.join(str(x) for x in obj). Every element is stringified, then joined. Nothing clever, nothing destructive - the input list isn't touched.

Inputs that matter

Two of them, and both are simple:

• obj (type *) - the list (or any iterable) to join.
• glue (STRING, default " ") - the separator placed between elements.

That default is worth a moment. Python's ",".join uses a comma, JavaScript's Array.join uses a comma, but this port defaults to a single space. Fine for building a sentence or a spaced tag list, but if you expected comma-separated output you'll wonder why nothing's separating. Set glue to ", " for tags or "/" for paths.

The output is one string, though it's typed * (ANY) rather than STRING - the generator didn't stamp this one, so a strict string socket might want a cast. Feed it a _.CHAIN and you get a chain back instead, resolved later with _.value.

Where it shines

Prompt fragments are the obvious one: build a list of style tags upstream, join them into a single prompt line. Filenames are another - combine a base name, counter, and extension into one path without a pile of concat nodes. And if you pair it with _.map, you can transform a list of dicts into a list of strings and then join that into a summary line.

The gotcha

Because everything gets str()-coerced, a dict element becomes its Python repr - {'a': 1} - which is almost never the label you wanted. Numbers become text happily (42 → "42"), but keep the input list to strings and simple scalars unless you enjoy debugging repr noise. Also, if you just want a join without the underscore machinery, the same pack has a plain List Join node in its Pystructure family; _.join is the variant that plays with chains and iteratees.

Installing comfy-ovum

ComfyUI Manager: search for comfy-ovum, install, restart. Or by hand:

cd ComfyUI/custom_nodes
git clone https://github.com/sfinktah/comfy-ovum
pip install -r comfy-ovum/requirements.txt

Restart and you're done. No model downloads, no CUDA - pure-Python utilities with a few small dependencies. Family caveat stands: the README calls these nodes a work in progress, though _.join is about as low-risk as this family gets.