react-is 19.2.8: isContextConsumer

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.isContextConsumer 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.isContextConsumer

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:sha256:4f20ce06004e5fd327d76ed2156ffba0bb72430de2a8e2e30578b21e1c7af260","contract":["isContextConsumer correctly identifies React Context Consumer element objects","isContextConsumer rejects plain DOM elements, provider elements, non-element objects, and primitives","typeOf returns ContextConsumer symbol for React Context Consumer element objects"],"goal":"verify react-is.isContextConsumer in pkg:npm/react-is@19.2.8","kind":"HOW","packages":["pkg:npm/react-is@19.2.8"],"schemaVersion":1,"symbols":["react-is.isContextConsumer"]},"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.isContextConsumer"],"verifierAdapter":"node-typescript@1"}

{
  "name": "sample-react-is-context-consumer",
  "version": "1.0.0",
  "lockfileVersion": 3,
  "requires": true,
  "packages": {
    "": {
      "name": "sample-react-is-context-consumer",
      "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-context-consumer",
  "version": "1.0.0",
  "private": true,
  "description": "Clean-room verification of react-is isContextConsumer in pkg:npm/react-is@19.2.8",
  "type": "module",
  "main": "src/index.js",
  "dependencies": {
    "react-is": "19.2.8"
  }
}

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

import { isContextConsumer, typeOf, ContextConsumer } from 'react-is';

/**
 * Check if the given value is a React Context Consumer element.
 *
 * @param {*} value - The value to inspect.
 * @returns {boolean} True if the value is a Context Consumer element.
 */
export function checkIsContextConsumer(value) {
  return isContextConsumer(value);
}

export { isContextConsumer, typeOf, ContextConsumer };

import assert from 'node:assert/strict';
import {
  checkIsContextConsumer,
  isContextConsumer,
  typeOf,
  ContextConsumer,
} from '../src/index.js';

// 1. Function and symbol exports verification
assert.equal(typeof isContextConsumer, 'function', 'isContextConsumer should be a function');
assert.equal(typeof checkIsContextConsumer, 'function', 'checkIsContextConsumer helper should be a function');
assert.equal(typeof ContextConsumer, 'symbol', 'ContextConsumer should be a symbol');
assert.equal(ContextConsumer, Symbol.for('react.consumer'), 'ContextConsumer matches react.consumer symbol');

// React 19 symbols
const REACT_ELEMENT_TYPE = Symbol.for('react.transitional.element');
const REACT_CONSUMER_TYPE = Symbol.for('react.consumer');
const REACT_CONTEXT_TYPE = Symbol.for('react.context');

// 2. Valid Context Consumer element
const consumerType = {
  $$typeof: REACT_CONSUMER_TYPE,
};

const consumerElement = {
  $$typeof: REACT_ELEMENT_TYPE,
  type: consumerType,
  props: { children: () => null },
  key: null,
  ref: null,
};

assert.equal(isContextConsumer(consumerElement), true, 'Valid Context Consumer element must be detected by isContextConsumer');
assert.equal(checkIsContextConsumer(consumerElement), true, 'checkIsContextConsumer helper must return true');
assert.equal(typeOf(consumerElement), ContextConsumer, 'typeOf(consumerElement) must equal ContextConsumer');

// 3. Reject Context Provider element
const providerType = {
  $$typeof: REACT_CONTEXT_TYPE,
};
const providerElement = {
  $$typeof: REACT_ELEMENT_TYPE,
  type: providerType,
  props: { value: 'test' },
  key: null,
  ref: null,
};

assert.equal(isContextConsumer(providerElement), false, 'Provider element must not be detected as Context Consumer');
assert.equal(checkIsContextConsumer(providerElement), false, 'checkIsContextConsumer returns false for Provider element');
assert.notEqual(typeOf(providerElement), ContextConsumer, 'typeOf(providerElement) must not equal ContextConsumer');

// 4. Reject plain DOM element
const divElement = {
  $$typeof: REACT_ELEMENT_TYPE,
  type: 'div',
  props: {},
  key: null,
  ref: null,
};

assert.equal(isContextConsumer(divElement), false, 'Plain DOM element must not be detected as Context Consumer');
assert.equal(checkIsContextConsumer(divElement), false, 'checkIsContextConsumer returns false for plain element');

// 5. Reject other React element types
const fragmentElement = {
  $$typeof: REACT_ELEMENT_TYPE,
  type: Symbol.for('react.fragment'),
  props: {},
  key: null,
  ref: null,
};
assert.equal(isContextConsumer(fragmentElement), false, 'Fragment element must not be detected as Context Consumer');

// 6. Reject non-element objects and primitives
assert.equal(isContextConsumer(null), false, 'null is not a Context Consumer');
assert.equal(isContextConsumer(undefined), false, 'undefined is not a Context Consumer');
assert.equal(isContextConsumer({}), false, 'plain object is not a Context Consumer');
assert.equal(isContextConsumer(consumerType), false, 'consumer type itself is not a Context Consumer element');
assert.equal(isContextConsumer('string'), false, 'string is not a Context Consumer');
assert.equal(isContextConsumer(123), false, 'number is not a Context Consumer');
assert.equal(checkIsContextConsumer(null), false, 'checkIsContextConsumer returns false for null');

console.log('Contract tests passed successfully.');