@tanstack/query-core 5.90.20: QueryCache

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 pkg:npm/%40tanstack/query-core@5.90.20
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:npm/%40tanstack/query-core@5.90.20
Demonstrate these symbols/APIs:
  - QueryCache

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:sha256:43f0927b3a0cb4897c925f5b152c6d2c0fd1dc87ba0ae86deadbf4ff7559b66d","contract":["assert QueryCache constructs an instance with cache lifecycle methods","assert QueryCache find retrieves an active query by exact queryKey or returns undefined","assert QueryCache findAll matches queries by key prefix or filter predicate","assert QueryCache subscribe notifies listeners of query lifecycle events: added, updated, removed","assert QueryCache remove removes a query and clear removes all cached queries","assert QueryCache unsubscribe stops listener notifications on subsequent cache events"],"goal":"verify pkg:npm/%40tanstack/query-core@5.90.20","kind":"HOW","packages":["pkg:npm/%40tanstack/query-core@5.90.20"],"schemaVersion":1,"symbols":["QueryCache"]},"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/%40tanstack/query-core@5.90.20"],"schemaVersion":1,"subject":"pkg:npm/%40tanstack/query-core@5.90.20","symbols":["QueryCache"],"verifierAdapter":"node-typescript@1"}

import { QueryCache, QueryClient } from '@tanstack/query-core';

/**
 * Creates a new QueryCache instance with optional configuration.
 *
 * @param {object} [config]
 * @returns {QueryCache}
 */
export function createQueryCache(config) {
  return new QueryCache(config);
}

/**
 * Subscribes a listener to QueryCache lifecycle events.
 *
 * @param {QueryCache} cache
 * @param {Function} listener
 * @returns {Function} Unsubscribe function
 */
export function subscribeQueryCache(cache, listener) {
  return cache.subscribe(listener);
}

/**
 * Finds a query by key within a QueryCache instance.
 *
 * @param {QueryCache} cache
 * @param {Array<string | number>} queryKey
 * @param {boolean} [exact=true]
 * @returns {object | undefined}
 */
export function findQuery(cache, queryKey, exact = true) {
  return cache.find({ queryKey, exact });
}

export { QueryCache, QueryClient };
export default QueryCache;

{
  "name": "sample-query-core-verify",
  "version": "1.0.0",
  "lockfileVersion": 3,
  "requires": true,
  "packages": {
    "": {
      "name": "sample-query-core-verify",
      "version": "1.0.0",
      "dependencies": {
        "@tanstack/query-core": "5.90.20"
      }
    },
    "node_modules/@tanstack/query-core": {
      "version": "5.90.20",
      "resolved": "https://registry.npmjs.org/@tanstack/query-core/-/query-core-5.90.20.tgz",
      "integrity": "sha512-OMD2HLpNouXEfZJWcKeVKUgQ5n+n3A2JFmBaScpNDUqSrQSjiveC7dKMe53uJUg1nDG16ttFPz2xfilz6i2uVg==",
      "license": "MIT",
      "funding": {
        "type": "github",
        "url": "https://github.com/sponsors/tannerlinsley"
      }
    }
  }
}

{
  "name": "sample-query-core-verify",
  "version": "1.0.0",
  "private": true,
  "type": "module",
  "dependencies": {
    "@tanstack/query-core": "5.90.20"
  }
}

{
  "schemaVersion": 1,
  "goal": "verify pkg:npm/%40tanstack/query-core@5.90.20",
  "kind": "HOW",
  "packages": [
    "pkg:npm/%40tanstack/query-core@5.90.20"
  ],
  "symbols": [
    "QueryCache"
  ]
}

import assert from 'node:assert/strict';
import { QueryCache, QueryClient, createQueryCache, subscribeQueryCache, findQuery } from '../index.mjs';

// 1. assert QueryCache constructs an instance with cache lifecycle methods
{
  const cache = createQueryCache();
  assert.ok(cache instanceof QueryCache);
  assert.strictEqual(typeof cache.find, 'function');
  assert.strictEqual(typeof cache.findAll, 'function');
  assert.strictEqual(typeof cache.subscribe, 'function');
  assert.strictEqual(typeof cache.clear, 'function');
  assert.strictEqual(typeof cache.getAll, 'function');
}

// 2. assert QueryCache find retrieves an active query by exact queryKey or returns undefined
{
  const cache = new QueryCache();
  const client = new QueryClient({ queryCache: cache });

  client.setQueryData(['users', 1], { id: 1, name: 'Alice' });

  const found = findQuery(cache, ['users', 1], true);
  assert.ok(found);
  assert.deepStrictEqual(found.state.data, { id: 1, name: 'Alice' });
  assert.strictEqual(found.state.status, 'success');

  const notFound = findQuery(cache, ['users', 2], true);
  assert.strictEqual(notFound, undefined);
}

// 3. assert QueryCache findAll matches queries by key prefix or filter predicate
{
  const cache = new QueryCache();
  const client = new QueryClient({ queryCache: cache });

  client.setQueryData(['todos', 1], 'Buy milk');
  client.setQueryData(['todos', 2], 'Read book');
  client.setQueryData(['posts', 1], 'Hello world');

  const todos = cache.findAll({ queryKey: ['todos'] });
  assert.strictEqual(todos.length, 2);

  const matchedKeys = todos.map(q => q.queryKey).sort();
  assert.deepStrictEqual(matchedKeys, [['todos', 1], ['todos', 2]]);

  const posts = cache.findAll({ predicate: (q) => q.queryKey[0] === 'posts' });
  assert.strictEqual(posts.length, 1);
  assert.deepStrictEqual(posts[0].queryKey, ['posts', 1]);
}

// 4. assert QueryCache subscribe notifies listeners of query lifecycle events: added, updated, removed
{
  const cache = new QueryCache();
  const client = new QueryClient({ queryCache: cache });

  const eventTypes = [];
  const unsubscribe = subscribeQueryCache(cache, (event) => {
    eventTypes.push(event.type);
  });

  client.setQueryData(['counter'], 1);
  client.setQueryData(['counter'], 2);

  const query = findQuery(cache, ['counter']);
  assert.ok(query);

  cache.remove(query);

  assert.ok(eventTypes.includes('added'));
  assert.ok(eventTypes.includes('updated'));
  assert.ok(eventTypes.includes('removed'));

  unsubscribe();
}

// 5. assert QueryCache remove removes a query and clear removes all cached queries
{
  const cache = new QueryCache();
  const client = new QueryClient({ queryCache: cache });

  client.setQueryData(['item', 1], 'first');
  client.setQueryData(['item', 2], 'second');
  client.setQueryData(['item', 3], 'third');

  assert.strictEqual(cache.getAll().length, 3);

  const query1 = findQuery(cache, ['item', 1]);
  cache.remove(query1);

  assert.strictEqual(cache.getAll().length, 2);
  assert.strictEqual(findQuery(cache, ['item', 1]), undefined);

  cache.clear();
  assert.strictEqual(cache.getAll().length, 0);
}

// 6. assert QueryCache unsubscribe stops listener notifications on subsequent cache events
{
  const cache = new QueryCache();
  const client = new QueryClient({ queryCache: cache });

  let notificationCount = 0;
  const unsubscribe = subscribeQueryCache(cache, () => {
    notificationCount++;
  });

  client.setQueryData(['test'], 'data');
  assert.ok(notificationCount > 0);

  const countBefore = notificationCount;
  unsubscribe();

  client.setQueryData(['test2'], 'data2');
  assert.strictEqual(notificationCount, countBefore);
}

console.log('All QueryCache contract assertions passed.');