`NonEmptyObject` fails for objects with dynamic properties

Description

import type { NonEmptyObject } from "type-fest"

interface CommonArguments {
  [filter: string]: NonEmptyObject<{ [argument: string]: string | number | undefined }>
}

export const commonArguments: CommonArguments = {
  foo: {}
}

Contributor guide

Tech stack

typescript

Domain

developer experience

Issue type

bug

DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.

3

Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.

half day

Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.

fresh

ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.

mostly clear

Prerequisites

understanding of TypeScript conditional typesfamiliarity with type fest utilities

Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.

40

Research direction

The issue is that the `NonEmptyObject` type does not correctly reject objects with index signatures when the object is empty. The problem lies in the type definition likely using a conditional type that checks if all keys are optional or similar. Investigate the current implementation in the source file (likely `source/non empty object.d.ts`). Consider adjusting the logic to handle index signatures by checking if the object has any known keys or if it is assignable to `Record<string, never>`. Review the TypeScript issue tracker for similar patterns. Look at linked PRs or comments for additional context.