react-is 19.2.8: ContextConsumer

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.ContextConsumer 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.ContextConsumer

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:sha256:642fa8745525ebd55cc75ff57726f0541e68ee26cd3b8e145f94d8321158d9c2","contract":["ContextConsumer is exported as a symbol identifying React context consumer elements","ContextConsumer symbol matches Symbol.for('react.consumer')","ContextConsumer is distinct from other React type symbols like ContextProvider and Element","typeOf returns ContextConsumer for React elements with a context consumer type object","isContextConsumer returns true for React elements matching ContextConsumer type and false otherwise"],"goal":"verify react-is.ContextConsumer in pkg:npm/react-is@19.2.8","kind":"HOW","packages":["pkg:npm/react-is@19.2.8"],"schemaVersion":1,"symbols":["react-is.ContextConsumer"]},"contractCommand":["node","test/contract.mjs"],"environment":{"arch":"x64","distro":"ubuntu","ecosystem":"npm","executionContext":"node","language":"javascript","libc":"glibc","libcVersion":"2.39","moduleSystem":"esm","os":"linux","osVersionBucket":"24","packageManager":"npm","packageManagerVersion":"10.9.8","runtime":"node","runtimeVersion":"22.23.2","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.ContextConsumer"],"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",
      "license": "MIT-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",
  "description": "Clean-room verification of react-is ContextConsumer in react-is@19.2.8",
  "type": "module",
  "private": true,
  "license": "MIT-0",
  "scripts": {
    "test": "node test/contract.mjs"
  },
  "dependencies": {
    "react-is": "19.2.8"
  }
}

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

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

/**
 * Returns the ContextConsumer type symbol exported by react-is.
 *
 * @returns {symbol} React context consumer type symbol
 */
export function getContextConsumerSymbol() {
  return ContextConsumer;
}

/**
 * Checks if a value is a React context consumer element.
 *
 * @param {*} value - The value to inspect
 * @returns {boolean} True if the value is a React context consumer element
 */
export function isConsumerElement(value) {
  return isContextConsumer(value);
}

/**
 * Determines the React type symbol of an element.
 *
 * @param {*} element - The React element to inspect
 * @returns {symbol|undefined} The element type symbol or undefined
 */
export function inspectElementType(element) {
  return typeOf(element);
}

export {
  ContextConsumer,
  ContextProvider,
  Element,
  isContextConsumer,
  typeOf,
};

import assert from 'node:assert/strict';
import {
  ContextConsumer,
  ContextProvider,
  Element,
  isContextConsumer,
  typeOf,
  getContextConsumerSymbol,
  isConsumerElement,
  inspectElementType,
} from '../src/index.js';

// 1. ContextConsumer is exported as a symbol identifying React context consumer elements
assert.equal(typeof ContextConsumer, 'symbol', 'ContextConsumer should be exported as a symbol');
assert.equal(getContextConsumerSymbol(), ContextConsumer, 'getContextConsumerSymbol() should return ContextConsumer');

// 2. ContextConsumer symbol matches Symbol.for('react.consumer')
assert.equal(ContextConsumer, Symbol.for('react.consumer'), 'ContextConsumer must equal Symbol.for("react.consumer")');

// 3. ContextConsumer is distinct from other React type symbols like ContextProvider and Element
assert.notEqual(ContextConsumer, ContextProvider, 'ContextConsumer must be distinct from ContextProvider');
assert.notEqual(ContextConsumer, Element, 'ContextConsumer must be distinct from Element');

// 4. typeOf returns ContextConsumer for React elements with a context consumer type object
const contextConsumerType = {
  $$typeof: ContextConsumer,
};
const contextConsumerElement = {
  $$typeof: Symbol.for('react.transitional.element'),
  type: contextConsumerType,
  props: {},
  key: null,
  ref: null,
};
assert.equal(typeOf(contextConsumerElement), ContextConsumer, 'typeOf must return ContextConsumer for context consumer element');
assert.equal(inspectElementType(contextConsumerElement), ContextConsumer, 'inspectElementType helper must return ContextConsumer');

// 5. isContextConsumer returns true for React elements matching ContextConsumer type and false otherwise
assert.equal(isContextConsumer(contextConsumerElement), true, 'isContextConsumer must return true for consumer element');
assert.equal(isConsumerElement(contextConsumerElement), true, 'isConsumerElement helper must return true for consumer element');

const contextProviderElement = {
  $$typeof: Symbol.for('react.transitional.element'),
  type: { $$typeof: ContextProvider },
  props: {},
  key: null,
  ref: null,
};
assert.equal(isContextConsumer(contextProviderElement), false, 'isContextConsumer must return false for provider element');
assert.equal(isConsumerElement(contextProviderElement), false, 'isConsumerElement helper must return false for provider element');

const plainElement = {
  $$typeof: Symbol.for('react.transitional.element'),
  type: 'div',
  props: {},
  key: null,
  ref: null,
};
assert.equal(isContextConsumer(plainElement), false, 'isContextConsumer must return false for plain element');
assert.equal(isConsumerElement(plainElement), false, 'isConsumerElement helper must return false for plain element');
assert.notEqual(typeOf(plainElement), ContextConsumer, 'plain element typeOf must not equal ContextConsumer');

assert.equal(isContextConsumer(null), false, 'isContextConsumer must return false for null');
assert.equal(isContextConsumer({}), false, 'isContextConsumer must return false for empty object');

console.log('All contract assertions for react-is.ContextConsumer passed.');