_.identity

_.identity doesn't do anything, and that's the whole point. Feed it any object and it hands you back the exact same object. It's the "identity function" from functional programming - the default iteratee that Underscore.js reaches for when you don't pass it a function - repackaged as a ComfyUI node with a _. name.

You're probably not going to build a production pipeline around it. But it earns its place in the ovum/underscore family as the safest possible test object: wire it anywhere you want to see what a value is without transforming it, or use it as a chain-compatible hop while you're still sketching a graph.

How it works

Under the hood, every one of these _. nodes is auto-generated from underscore3, a Python port of Underscore.js bundled inside the pack. The method itself is about as minimal as code gets:

def identity(self, *args):
    return self._wrap(self.obj)

It wraps your input object and returns it unchanged. The node's run unwraps that wrapper, so what comes out the * output is literally the same Python object that went in.

The fun part is chain compatibility. Its primary obj input also accepts a _.CHAIN produced by the pack's _.chain node. Feed _.identity a chain and it hands the chain back, so you can drop it in the middle of a _.chain → method → _.value pipeline as a no-op and keep chaining.

The inputs that matter

There are only two, both optional:

• obj - the primary input. Anything goes, since it's typed *. This is also where you'd attach a _.CHAIN to continue a chain.
• args - leftover from the varargs plumbing of the generator. The tooltip says to use a JSON array (like [1,2,3]) for multiple values. You can ignore it; identity doesn't consume it in any meaningful way.

Output is a single * - untyped, because the generator couldn't guess what type an "identity" produces. That's fine: whatever you put in, you get back out.

Installing

_.identity ships in comfy-ovum, sfinktah's personal grab-bag of ComfyUI utilities (MIT licensed). The easy path is ComfyUI Manager - search comfy-ovum and install, then restart. Or by hand:

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

then restart ComfyUI. Note you're installing the whole pack, which drags in its requirements.txt - pymediainfo, tomli-w, requests, braceexpand, pillow, numpy, markdown-it-py, aiohttp. The one that bites on Linux is pymediainfo, which wants the system libmediainfo library. The underscore nodes themselves need nothing extra; they run on the underscore3 port bundled right in the repo.

Verdict

The README is blunt that the underscore nodes are a work in progress and "an absolute disaster to use in production." For _.identity specifically, that's overstating it - this one is too simple to break. Just know it's a passthrough. If you genuinely want a do-nothing hop with a defined type, a core reroute or the pack's dedicated passthrough nodes are usually more useful. Reach for _.identity when you want the concept of identity in a chain, not when you need plumbing.