jest-regex-util 29.6.3: Escape special regex characters in strings using jest-regex-util escapeStrForRegex

This contract measures the behavior of `escapeStrForRegex` from `jest-regex-util@29.6.3`.

It asserts that all regular expression metacharacters (`[`, `]`, `{`, `}`, `(`, `)`, `*`, `+`, `?`, `.`, `\`, `^`, `$`, `|`) are escaped with a preceding backslash, ensuring that a `RegExp` constructed from the escaped string matches the input literally and that strings without metacharacters remain unaltered.

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: Escape special regex characters in strings using jest-regex-util escapeStrForRegex
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:npm/jest-regex-util@29.6.3

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.

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{
  "name": "sample-jest-regex-util",
  "version": "1.0.0",
  "lockfileVersion": 3,
  "requires": true,
  "packages": {
    "": {
      "name": "sample-jest-regex-util",
      "version": "1.0.0",
      "license": "MIT-0",
      "dependencies": {
        "jest-regex-util": "29.6.3"
      }
    },
    "node_modules/jest-regex-util": {
      "version": "29.6.3",
      "resolved": "https://registry.npmjs.org/jest-regex-util/-/jest-regex-util-29.6.3.tgz",
      "integrity": "sha512-KJJBsRCyyLNWCNBOvZyRDnAIfUiRJ8v+hOBQYGn8gDyF3UegwiP4gwRR3/SDa42g1YbVycTidUF3rKjyLFDWbg==",
      "license": "MIT",
      "engines": {
        "node": "^14.15.0 || ^16.10.0 || >=18.0.0"
      }
    }
  }
}

{
  "name": "sample-jest-regex-util",
  "version": "1.0.0",
  "private": true,
  "type": "module",
  "license": "MIT-0",
  "scripts": {
    "test": "node test/contract.mjs"
  },
  "dependencies": {
    "jest-regex-util": "29.6.3"
  }
}

{
  "schemaVersion": 1,
  "goal": "Escape special regex characters in strings using jest-regex-util escapeStrForRegex",
  "kind": "HOW",
  "packages": [
    "pkg:npm/jest-regex-util@29.6.3"
  ]
}

import assert from 'node:assert/strict';
import { escapeStrForRegex } from 'jest-regex-util';

// 1. Assert each special regex character is escaped with a backslash
const metacharacters = ['[', ']', '{', '}', '(', ')', '*', '+', '?', '.', '\\', '^', '$', '|'];
for (const char of metacharacters) {
  assert.equal(
    escapeStrForRegex(char),
    `\\${char}`,
    `escapeStrForRegex should escape regular expression character: ${char}`
  );
}

// 2. Assert escapeStrForRegex escapes all metacharacters within a complex string
const complexInput = 'resource (v1.0) [dev] *+?^$|{}';
const escaped = escapeStrForRegex(complexInput);
assert.equal(
  escaped,
  'resource \\(v1\\.0\\) \\[dev\\] \\*\\+\\?\\^\\$\\|\\{\\}',
  'escapeStrForRegex should escape all regex metacharacters in a complex string'
);

// 3. Assert RegExp constructed from escaped string matches the original string literally
const pattern = new RegExp(`^${escaped}$`);
assert.ok(
  pattern.test(complexInput),
  'RegExp compiled from escaped string must match original string verbatim'
);

// 4. Assert strings without regex metacharacters are unchanged
const alphanumeric = 'standard_filename-123';
assert.equal(
  escapeStrForRegex(alphanumeric),
  alphanumeric,
  'escapeStrForRegex should not modify strings without regex metacharacters'
);