sindresorhus/eslint-plugin-unicorn

False positive: 'promise.withresolvers' in 'no-unnecessary-polyfills'

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#2,404 opened on Jul 22, 2024

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Description

The no-unnecessary-polyfills rule complains about usage of promise.withresolvers package on Node.js 20 even though the native Promise.withResolvers is not available. According to MDN, it is only available since Node 22.0.0.

no-unnecessary-polyfills

Here's my rule config:

"unicorn/no-unnecessary-polyfills": [
    "error",
    { targets: "node 20.15.0" },
],

Here's the engines part on package.json:

    "engines": {
        "node": "^20.15.0",
        "pnpm": "^9.4.0"
    },

And there's a piece of code that triggers an error.

import withResolvers from "promise.withresolvers"; // Use built-in instead. eslint (unicorn/no-unnecessary-polyfills)

Contributor guide

Research direction
The issue is a false positive in the no unnecessary polyfills rule due to incorrect target version mapping for Promise.withResolvers. To fix, locate the data structure in the rule's source file (likely rules/no unnecessary polyfills.js) that defines which native APIs are available per Node version. Add Promise.withResolvers as available from Node 22.0.0. The issue includes a clear reproduction with configuration and code example.
Tech stack
javascripttypescript
Domain
toolingdeveloper experience
Issue type
Bug
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
2
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
Under 1 hour
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.
Clear
Prerequisites
JavaScriptESLint plugin internals
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
80