@vitest/utils 4.1.10: stringify

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 @vitest/utils.stringify in pkg:npm/%40vitest/utils@4.1.10
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:npm/%40vitest/utils@4.1.10
Demonstrate these symbols/APIs:
  - @vitest/utils.stringify

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:sha256:60ec38060c3503dbf7cac5f56fa718559b40bdc1690f04bdc95bbbe3fe3b18a7","contract":["stringify formats primitive values including numbers, strings, booleans, null, undefined, symbols, and bigints","stringify formats objects and arrays with structured indentation and sorted keys","stringify respects maxDepth limit by truncating nested structures beyond the limit","stringify supports custom formatting options including indent and callToJSON","stringify reduces traversal depth when serialized output exceeds maxLength threshold","stringify formats circular references and built-in objects safely"],"goal":"verify @vitest/utils.stringify in pkg:npm/%40vitest/utils@4.1.10","kind":"HOW","packages":["pkg:npm/%40vitest/utils@4.1.10"],"schemaVersion":1,"symbols":["@vitest/utils.stringify"]},"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/%40vitest/utils@4.1.10"],"schemaVersion":1,"subject":"pkg:npm/%40vitest/utils@4.1.10","symbols":["@vitest/utils.stringify"],"verifierAdapter":"node-typescript@1"}

import { stringify } from '@vitest/utils/display';

export { stringify };

/**
 * Formats any JavaScript value into a human-readable string representation.
 * @param {unknown} value - The value to serialize.
 * @param {number} [maxDepth=10] - Maximum traversal depth.
 * @param {object} [options={}] - Additional formatting options.
 * @returns {string} Formatted string.
 */
export function formatValue(value, maxDepth = 10, options = {}) {
  return stringify(value, maxDepth, options);
}

/**
 * Formats a value with a bounded output length constraint.
 * @param {unknown} value - The value to serialize.
 * @param {number} maxLength - Maximum character length threshold.
 * @returns {string} Formatted string.
 */
export function formatWithLimit(value, maxLength) {
  return stringify(value, 10, { maxLength });
}

{
  "name": "sample-vitest-utils-stringify",
  "version": "1.0.0",
  "lockfileVersion": 3,
  "requires": true,
  "packages": {
    "": {
      "name": "sample-vitest-utils-stringify",
      "version": "1.0.0",
      "dependencies": {
        "@vitest/utils": "4.1.10"
      }
    },
    "node_modules/@vitest/pretty-format": {
      "version": "4.1.10",
      "resolved": "https://registry.npmjs.org/@vitest/pretty-format/-/pretty-format-4.1.10.tgz",
      "integrity": "sha512-W1HsjSH4MXQ9YfmmhLAoIYf1HRfekQCGngeIgcei6MP5QQGWUe0gkopdZQaVCFO+JDJMrAJGwa5pRpNpvy4P8Q==",
      "license": "MIT",
      "dependencies": {
        "tinyrainbow": "^3.1.0"
      },
      "funding": {
        "url": "https://opencollective.com/vitest"
      }
    },
    "node_modules/@vitest/utils": {
      "version": "4.1.10",
      "resolved": "https://registry.npmjs.org/@vitest/utils/-/utils-4.1.10.tgz",
      "integrity": "sha512-fy9am/HWxbaGt/Sawrp90vt6Y6jQwf1RX77cz3uwoJwJVMli/e1IEwRPnMNJ7vKfPTwo0diXifkpPvwH9v7nGA==",
      "license": "MIT",
      "dependencies": {
        "@vitest/pretty-format": "4.1.10",
        "convert-source-map": "^2.0.0",
        "tinyrainbow": "^3.1.0"
      },
      "funding": {
        "url": "https://opencollective.com/vitest"
      }
    },
    "node_modules/convert-source-map": {
      "version": "2.0.0",
      "resolved": "https://registry.npmjs.org/convert-source-map/-/convert-source-map-2.0.0.tgz",
      "integrity": "sha512-Kvp459HrV2FEJ1CAsi1Ku+MY3kasH19TFykTz2xWmMeq6bk2NU3XXvfJ+Q61m0xktWwt+1HSYf3JZsTms3aRJg==",
      "license": "MIT"
    },
    "node_modules/tinyrainbow": {
      "version": "3.1.1",
      "resolved": "https://registry.npmjs.org/tinyrainbow/-/tinyrainbow-3.1.1.tgz",
      "integrity": "sha512-yau8yJdTt989Mm0Bd/236QnzEiPf2xLLTqUZRUJOo/3CB078LSwzei343DgtJVmfJKJE3TMINY1u42SQsP6mXw==",
      "license": "MIT",
      "engines": {
        "node": ">=14.0.0"
      }
    }
  }
}

{
  "name": "sample-vitest-utils-stringify",
  "version": "1.0.0",
  "description": "Clean-room verification sample for @vitest/utils stringify",
  "type": "module",
  "main": "index.mjs",
  "scripts": {
    "test": "node test/contract.mjs"
  },
  "dependencies": {
    "@vitest/utils": "4.1.10"
  }
}

{
  "schemaVersion": 1,
  "goal": "verify @vitest/utils.stringify in pkg:npm/%40vitest/utils@4.1.10",
  "kind": "HOW",
  "packages": [
    "pkg:npm/%40vitest/utils@4.1.10"
  ],
  "symbols": [
    "@vitest/utils.stringify"
  ]
}

import assert from 'node:assert/strict';
import { stringify } from '@vitest/utils/display';
import { formatValue, formatWithLimit } from '../index.mjs';

// 1. stringify formats primitive values including numbers, strings, booleans, null, undefined, symbols, and bigints
{
  assert.equal(stringify(42), '42');
  assert.equal(stringify(-0), '-0');
  assert.equal(stringify('hello'), '"hello"');
  assert.equal(stringify(''), '""');
  assert.equal(stringify(true), 'true');
  assert.equal(stringify(false), 'false');
  assert.equal(stringify(null), 'null');
  assert.equal(stringify(undefined), 'undefined');
  assert.equal(stringify(Symbol('token')), 'Symbol(token)');
  assert.equal(stringify(100n), '100n');
}

// 2. stringify formats objects and arrays with structured indentation and sorted keys
{
  const arr = [1, 'two', true];
  assert.equal(stringify(arr), 'Array [\n  1,\n  "two",\n  true,\n]');

  const obj = { beta: 2, alpha: 1 };
  assert.equal(stringify(obj), 'Object {\n  "alpha": 1,\n  "beta": 2,\n}');

  // Helper formatValue check
  assert.equal(formatValue(arr), 'Array [\n  1,\n  "two",\n  true,\n]');
}

// 3. stringify respects maxDepth limit by truncating nested structures beyond the limit
{
  const nested = {
    level1: {
      level2: {
        level3: 'deep',
      },
    },
  };
  assert.equal(stringify(nested, 1), 'Object {\n  "level1": [Object],\n}');
  assert.equal(
    stringify(nested, 2),
    'Object {\n  "level1": Object {\n    "level2": [Object],\n  },\n}'
  );
}

// 4. stringify supports custom formatting options including indent and callToJSON
{
  const target = { x: 10 };
  assert.equal(stringify(target, 10, { indent: 4 }), 'Object {\n    "x": 10,\n}');

  const withToJSON = {
    original: 'val',
    toJSON() {
      return { converted: true };
    },
  };
  assert.equal(stringify(withToJSON), 'Object {\n  "converted": true,\n}');
  assert.equal(
    stringify(withToJSON, 10, { callToJSON: false }),
    'Object {\n  "original": "val",\n  "toJSON": [Function toJSON],\n}'
  );
}

// 5. stringify reduces traversal depth when serialized output exceeds maxLength threshold
{
  const deepObj = {
    level1: {
      level2: {
        level3: {
          value: 'some long string content here',
        },
      },
    },
  };
  const limited = stringify(deepObj, 10, { maxLength: 50 });
  assert.equal(limited, 'Object {\n  "level1": [Object],\n}');

  // Helper formatWithLimit check
  const helperLimited = formatWithLimit(deepObj, 50);
  assert.equal(helperLimited, 'Object {\n  "level1": [Object],\n}');
}

// 6. stringify formats circular references and built-in objects safely
{
  const cycle = { name: 'self-ref' };
  cycle.loop = cycle;
  assert.equal(
    stringify(cycle),
    'Object {\n  "loop": [Circular],\n  "name": "self-ref",\n}'
  );

  assert.equal(
    stringify(new Date('2026-01-01T00:00:00.000Z')),
    '2026-01-01T00:00:00.000Z'
  );
  assert.equal(stringify(/test-regex/i), '/test-regex/i');

  const map = new Map([['k1', 'v1']]);
  assert.equal(stringify(map), 'Map {\n  "k1" => "v1",\n}');

  const set = new Set(['val1', 'val2']);
  assert.equal(stringify(set), 'Set {\n  "val1",\n  "val2",\n}');
}

console.log('All @vitest/utils.stringify contract assertions passed.');