@tanstack/query-core 5.90.20: focusManager

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:
  - focusManager

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:sha256:336a6a510773f20dacf929a9e22ac249580cb835c7d1e3213791d18a9475a9dc","contract":["assert focusManager isFocused returns true by default in node environment","assert focusManager setFocused updates focus state and notifies subscribed listeners","assert focusManager setFocused deduplicates notifications when state is unchanged","assert focusManager unsubscribe stops listener notifications on subsequent focus changes","assert focusManager setFocused with undefined resets focus state back to default","assert focusManager setEventListener enables custom event listener configuration"],"goal":"verify pkg:npm/%40tanstack/query-core@5.90.20","kind":"HOW","packages":["pkg:npm/%40tanstack/query-core@5.90.20"],"schemaVersion":1,"symbols":["focusManager"]},"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":["focusManager"],"verifierAdapter":"node-typescript@1"}

import { focusManager } from '@tanstack/query-core';

/**
 * Returns whether the focusManager currently considers the environment focused.
 *
 * @returns {boolean}
 */
export function isCurrentlyFocused() {
  return focusManager.isFocused();
}

/**
 * Explicitly sets the focus state.
 *
 * @param {boolean | undefined} focused
 */
export function setFocusState(focused) {
  focusManager.setFocused(focused);
}

/**
 * Subscribes a listener to focus state changes.
 *
 * @param {Function} listener
 * @returns {Function} Unsubscribe function
 */
export function subscribeToFocus(listener) {
  return focusManager.subscribe(listener);
}

/**
 * Configures a custom event listener setup function.
 *
 * @param {Function} setup
 */
export function configureFocusEventListener(setup) {
  focusManager.setEventListener(setup);
}

export { focusManager };
export default focusManager;

{
  "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": [
    "focusManager"
  ]
}

import assert from 'node:assert/strict';
import {
  focusManager,
  isCurrentlyFocused,
  setFocusState,
  subscribeToFocus,
  configureFocusEventListener,
} from '../index.mjs';

// 1. assert focusManager isFocused returns true by default in node environment
{
  assert.strictEqual(typeof focusManager.isFocused, 'function');
  assert.strictEqual(typeof focusManager.setFocused, 'function');
  assert.strictEqual(typeof focusManager.subscribe, 'function');
  assert.strictEqual(typeof focusManager.setEventListener, 'function');
  assert.strictEqual(isCurrentlyFocused(), true);
}

// 2. assert focusManager setFocused updates focus state and notifies subscribed listeners
{
  let notifiedState = null;
  let callCount = 0;
  const unsubscribe = subscribeToFocus((focused) => {
    callCount++;
    notifiedState = focused;
  });

  setFocusState(false);
  assert.strictEqual(isCurrentlyFocused(), false);
  assert.strictEqual(callCount, 1);
  assert.strictEqual(notifiedState, false);

  setFocusState(true);
  assert.strictEqual(isCurrentlyFocused(), true);
  assert.strictEqual(callCount, 2);
  assert.strictEqual(notifiedState, true);

  unsubscribe();
}

// 3. assert focusManager setFocused deduplicates notifications when state is unchanged
{
  let callCount = 0;
  const unsubscribe = subscribeToFocus(() => {
    callCount++;
  });

  setFocusState(true);
  assert.strictEqual(callCount, 0);

  setFocusState(false);
  assert.strictEqual(callCount, 1);

  setFocusState(false);
  assert.strictEqual(callCount, 1);

  unsubscribe();
  setFocusState(true);
}

// 4. assert focusManager unsubscribe stops listener notifications on subsequent focus changes
{
  let callCount = 0;
  const unsubscribe = subscribeToFocus(() => {
    callCount++;
  });

  setFocusState(false);
  assert.strictEqual(callCount, 1);

  unsubscribe();

  setFocusState(true);
  assert.strictEqual(callCount, 1);
}

// 5. assert focusManager setFocused with undefined resets focus state back to default
{
  setFocusState(false);
  assert.strictEqual(isCurrentlyFocused(), false);

  setFocusState(undefined);
  assert.strictEqual(isCurrentlyFocused(), true);
}

// 6. assert focusManager setEventListener enables custom event listener configuration
{
  let cleanupCalled = false;
  let customTrigger = null;

  configureFocusEventListener((onFocus) => {
    customTrigger = onFocus;
    return () => {
      cleanupCalled = true;
    };
  });

  assert.strictEqual(typeof customTrigger, 'function');

  let listenerState = null;
  const unsubscribe = subscribeToFocus((focused) => {
    listenerState = focused;
  });

  customTrigger(false);
  assert.strictEqual(isCurrentlyFocused(), false);
  assert.strictEqual(listenerState, false);

  customTrigger(true);
  assert.strictEqual(isCurrentlyFocused(), true);
  assert.strictEqual(listenerState, true);

  customTrigger();
  assert.strictEqual(isCurrentlyFocused(), true);

  unsubscribe();

  configureFocusEventListener(() => () => {});
  assert.strictEqual(cleanupCalled, true);
  setFocusState(true);
}

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