---
title: ArgNames
description: A type that the Authoring surface names.
---

# `ArgNames`

Type, in `@jr2/orchestrator/src/effect.ts`. It is type plumbing: it computes a type from the types of a Machine or of its parts, and a workflow module does not write it. The signature of an export, or a type that it names, names this type, so its declaration is here. The [Authoring surface](../authoring-surface.md) page lists each export.

```ts
type ArgNames<A extends readonly unknown[]> = A[number] extends infer E ? (E extends Arg<infer N> ? N : never) : never;
```