react-is 19.2.8: isForwardRef

Clean-room public code sample — generation instructions

Write a brand-new, minimal, self-contained code sample in this clean-room directory.
Do not copy, paraphrase, or reference any existing project source. Work only from this spec.

A csx.json manifest scaffold already exists. Do not recreate it from memory. Preserve its case.goal, packages and symbols; fill its empty case.contract with exact assertions and correct its environment, commands and verifierAdapter for the files you generate.

Goal: verify react-is.isForwardRef in pkg:npm/react-is@19.2.8
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:npm/react-is@19.2.8
Demonstrate these symbols/APIs:
  - react-is.isForwardRef

Rules:
  - One focused purpose; the smallest project that proves the goal.
  - Include a contract test (test/contract.*) that runs OFFLINE and exits 0 exactly when the goal behavior works.
  - Pin every dependency with a lockfile so resolution is reproducible.
  - No secrets, credentials, or tokens. No real URLs (only example.com or localhost). No absolute paths.
  - No personal names, emails, company names, or project identifiers of any kind.
  - No binaries and no generated output (node_modules, dist, target, venv, .git, .env).
  - Keep it under 200 files and 256KB packed.

{"case":{"caseId":"case:sha256:1d73c955d4a34a0b4479e246c5e151063a36e6b3f46b1fdde2adf61dc9623849","contract":["isForwardRef is exported as a function","isForwardRef identifies React elements created with forward_ref component types","isForwardRef rejects standard React elements","isForwardRef rejects raw forward_ref component objects not wrapped in a React element","isForwardRef rejects empty objects, primitives, null, and undefined"],"goal":"verify react-is.isForwardRef in pkg:npm/react-is@19.2.8","kind":"HOW","packages":["pkg:npm/react-is@19.2.8"],"schemaVersion":1,"symbols":["react-is.isForwardRef"]},"contractCommand":["node","test/contract.mjs"],"environment":{"arch":"x64","distro":"ubuntu","ecosystem":"npm","libc":"glibc","libcVersion":"2.39","os":"linux","osVersionBucket":"24","packageManager":"npm","schemaVersion":1},"license":"MIT-0","packages":["pkg:npm/react-is@19.2.8"],"schemaVersion":1,"subject":"pkg:npm/react-is@19.2.8","symbols":["react-is.isForwardRef"],"verifierAdapter":"node-typescript@1"}

{
  "name": "sample-react-is-forwardref",
  "version": "1.0.0",
  "lockfileVersion": 3,
  "requires": true,
  "packages": {
    "": {
      "name": "sample-react-is-forwardref",
      "version": "1.0.0",
      "dependencies": {
        "react-is": "19.2.8"
      }
    },
    "node_modules/react-is": {
      "version": "19.2.8",
      "resolved": "https://registry.npmjs.org/react-is/-/react-is-19.2.8.tgz",
      "integrity": "sha512-s5un28nYxKJw5gvUHyW5PCC28CvBqLu9r3cWgzHT4Vo/5fqqkFcdRYsGcKf50WMPpjjFZS5d76fn3YCo2njKwQ==",
      "license": "MIT"
    }
  }
}

{
  "name": "sample-react-is-forwardref",
  "version": "1.0.0",
  "private": true,
  "description": "Clean-room verification of react-is 19.2.8 isForwardRef API",
  "type": "module",
  "main": "src/index.js",
  "dependencies": {
    "react-is": "19.2.8"
  }
}

{
  "schemaVersion": 1,
  "goal": "verify react-is.isForwardRef in pkg:npm/react-is@19.2.8",
  "kind": "HOW",
  "packages": [
    "pkg:npm/react-is@19.2.8"
  ],
  "symbols": [
    "react-is.isForwardRef"
  ]
}

import { isForwardRef, ForwardRef, Element } from 'react-is';

/**
 * Check if the given value is a React forwardRef element.
 *
 * @param {*} value - The value to check.
 * @returns {boolean} True if the value is a forwardRef element.
 */
export function checkIsForwardRef(value) {
  return isForwardRef(value);
}

export { isForwardRef, ForwardRef, Element };

import assert from 'node:assert/strict';
import {
  isForwardRef,
  checkIsForwardRef,
  ForwardRef,
  Element,
} from '../src/index.js';

// 1. Function and constant exports verification
assert.equal(typeof isForwardRef, 'function', 'isForwardRef should be a function');
assert.equal(typeof checkIsForwardRef, 'function', 'checkIsForwardRef helper should be a function');
assert.equal(typeof ForwardRef, 'symbol', 'ForwardRef should be a symbol');
assert.equal(typeof Element, 'symbol', 'Element should be a symbol');

// 2. React ForwardRef element detection
const forwardRefComponent = {
  $$typeof: ForwardRef,
  render: (props, ref) => null,
};

const forwardRefElement = {
  $$typeof: Element,
  type: forwardRefComponent,
  props: {},
  key: null,
  ref: null,
};

assert.equal(isForwardRef(forwardRefElement), true, 'ForwardRef element must be identified by isForwardRef');
assert.equal(checkIsForwardRef(forwardRefElement), true, 'checkIsForwardRef helper must return true for ForwardRef element');

// 3. Rejection of standard React elements
const standardElement = {
  $$typeof: Element,
  type: 'div',
  props: {},
  key: null,
  ref: null,
};

assert.equal(isForwardRef(standardElement), false, 'Standard element must not be identified as ForwardRef');
assert.equal(checkIsForwardRef(standardElement), false, 'checkIsForwardRef helper must return false for standard element');

// 4. Rejection of raw forward_ref component types not wrapped in a React element
assert.equal(isForwardRef(forwardRefComponent), false, 'Raw forward_ref component type is not a React element');
assert.equal(checkIsForwardRef(forwardRefComponent), false, 'checkIsForwardRef helper must return false for raw component type');

// 5. Rejection of empty objects, primitives, null, and undefined
assert.equal(isForwardRef({}), false, 'Empty object is not a forwardRef');
assert.equal(isForwardRef(null), false, 'null is not a forwardRef');
assert.equal(isForwardRef(undefined), false, 'undefined is not a forwardRef');
assert.equal(isForwardRef('react.forward_ref'), false, 'string is not a forwardRef');
assert.equal(isForwardRef(12345), false, 'number is not a forwardRef');
assert.equal(isForwardRef(() => null), false, 'function is not a forwardRef');