_.only

_.only is the "keep just these" filter. Give it a list and a set of values, and it returns only the elements that match. Give it a dict and a set of keys, and it returns only those entries. It's the inverse of _.without, and a list-friendly cousin of _.pick.

What it does

The behavior switches on what you feed it:

• Lists - [1, 2, 3, 4, 5] with values 2, 4 returns [2, 4]. It keeps elements whose value is in your keep-list.
• Dicts - {"a": 1, "b": 2, "c": 3} with keys a, c returns {"a": 1, "c": 3}. It keeps entries whose key is in your keep-list.

Same node, two personalities, decided by the input type. That dual behavior is the thing to remember - on a dict it filters keys, on a list it filters values.

The inputs:

• obj - the list or dict (or a _.CHAIN)
• values - the keep-list. For multiple values, pass a JSON array like [1,2,3]; the tooltip is explicit about this

Output is a single ANY slot that carries whatever you put in, filtered.

The JSON-array habit

values is an ANY socket, and the one mistake people make is typing 1, 2, 3 into it and getting nothing sensible back. This family parses JSON on those inputs, so you want [1, 2, 3] for a keep-list of several values. A single value works bare, but get into the habit of JSON arrays early - it transfers to _.pick, _.omit and the predicate nodes in the same pack.

Where it fits

The realistic use is data hygiene: you've got a list of candidate values and you only care about a few of them, or you've got a dict and you're keeping a short allowlist of keys. It's a niche that overlaps with _.pick, but _.only also handles lists, which pick doesn't. For "this dict but only these three fields," _.pick is arguably clearer; for "this list but only these values," _.only is the one.

Installing

Ships in comfy-ovum. ComfyUI Manager → search comfy-ovum → Install, or:

cd ComfyUI/custom_nodes
git clone https://github.com/sfinktah/comfy-ovum

Restart ComfyUI. No models, no extra pip packages for the underscore nodes - the underscore.js port is bundled in the repo.

The bottom line

A dual-mode keep-filter: values for lists, keys for dicts. Feed it JSON arrays for multiple keep-items and it'll do exactly what the name promises.