@babel/types 7.29.8: isValidIdentifier

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 @babel/types.isValidIdentifier in pkg:npm/%40babel/types@7.29.8
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:npm/%40babel/types@7.29.8
Demonstrate these symbols/APIs:
  - @babel/types.isValidIdentifier
Constraints:
  - executionContext: node
Required runtime conditions:
  - ecosystem: npm
  - language: javascript
  - moduleSystem: cjs
  - packageManager: npm@10.9.8
  - runtime: node@22.23.2

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:sha256:711b96949163bcce374345dbea2bac21ea7c3e14df27e3a0ab67525654825d9c","constraints":{"executionContext":"node"},"contract":["isValidIdentifier returns true for standard identifier names including alphanumeric characters, dollar signs, and underscores","isValidIdentifier returns false for JavaScript reserved words and keywords when reserved check is enabled by default","isValidIdentifier returns true for reserved words and keywords when reserved check is set to false","isValidIdentifier returns false for strings with invalid identifier characters, digits at start, empty strings, or non-string inputs"],"goal":"verify @babel/types.isValidIdentifier in pkg:npm/%40babel/types@7.29.8","kind":"HOW","packages":["pkg:npm/%40babel/types@7.29.8"],"schemaVersion":1,"symbols":["@babel/types.isValidIdentifier"]},"contractCommand":["node","test/contract.mjs"],"environment":{"arch":"x64","distro":"ubuntu","ecosystem":"npm","executionContext":"node","language":"javascript","libc":"glibc","libcVersion":"2.39","moduleSystem":"cjs","os":"linux","osVersionBucket":"24","packageManager":"npm","packageManagerVersion":"10.9.8","runtime":"node","runtimeVersion":"22.23.2","schemaVersion":1},"license":"MIT-0","packages":["pkg:npm/%40babel/types@7.29.8"],"schemaVersion":1,"subject":"pkg:npm/%40babel/types@7.29.8","symbols":["@babel/types.isValidIdentifier"],"verifierAdapter":"node-typescript@1"}

{
  "name": "sample-babel-types-is-valid-identifier",
  "version": "1.0.0",
  "lockfileVersion": 3,
  "requires": true,
  "packages": {
    "": {
      "name": "sample-babel-types-is-valid-identifier",
      "version": "1.0.0",
      "license": "MIT-0",
      "dependencies": {
        "@babel/types": "7.29.8"
      }
    },
    "node_modules/@babel/helper-string-parser": {
      "version": "7.29.7",
      "resolved": "https://registry.npmjs.org/@babel/helper-string-parser/-/helper-string-parser-7.29.7.tgz",
      "integrity": "sha512-Pb5ijPrZ89GDH8223L4UP8i6QApWxs04RbPQJTeWDV0/keR2E36MeKnyr6LYmUUvqRRI+Iv87SuF1W6ErINzYw==",
      "license": "MIT",
      "engines": {
        "node": ">=6.9.0"
      }
    },
    "node_modules/@babel/helper-validator-identifier": {
      "version": "7.29.7",
      "resolved": "https://registry.npmjs.org/@babel/helper-validator-identifier/-/helper-validator-identifier-7.29.7.tgz",
      "integrity": "sha512-qehxGkRj55h/ff8EMaJ+cYhyaKlHIxqYDn682wQD7RNp9UujOQsHog2uS0r2vzr4pW+sXf90NeeayjcNaX3fFg==",
      "license": "MIT",
      "engines": {
        "node": ">=6.9.0"
      }
    },
    "node_modules/@babel/types": {
      "version": "7.29.8",
      "resolved": "https://registry.npmjs.org/@babel/types/-/types-7.29.8.tgz",
      "integrity": "sha512-Vj1jF3cPfxg7OAfoI7QnVKLoILlm2JF9pnVHrX8qx7AHMiYWT+NDAA7jChlNgRS4WTLc/fD1lXLmPixluj+3Gg==",
      "license": "MIT",
      "dependencies": {
        "@babel/helper-string-parser": "^7.29.7",
        "@babel/helper-validator-identifier": "^7.29.7"
      },
      "engines": {
        "node": ">=6.9.0"
      }
    }
  }
}

{
  "name": "sample-babel-types-is-valid-identifier",
  "version": "1.0.0",
  "private": true,
  "type": "module",
  "license": "MIT-0",
  "dependencies": {
    "@babel/types": "7.29.8"
  }
}

{
  "schemaVersion": 1,
  "goal": "verify @babel/types.isValidIdentifier in pkg:npm/%40babel/types@7.29.8",
  "kind": "HOW",
  "packages": [
    "pkg:npm/%40babel/types@7.29.8"
  ],
  "symbols": [
    "@babel/types.isValidIdentifier"
  ],
  "constraints": {
    "executionContext": "node"
  },
  "runtimeConditions": {
    "ecosystem": "npm",
    "language": "javascript",
    "moduleSystem": "cjs",
    "packageManager": "npm@10.9.8",
    "runtime": "node@22.23.2"
  }
}

import * as t from "@babel/types";

export function checkValidIdentifier(name, reserved) {
  return t.isValidIdentifier(name, reserved);
}

export function isAllowedIdentifier(name) {
  return t.isValidIdentifier(name);
}

export function isAllowedPropertyName(name) {
  return t.isValidIdentifier(name, false);
}

import assert from "node:assert/strict";
import * as t from "@babel/types";
import {
  checkValidIdentifier,
  isAllowedIdentifier,
  isAllowedPropertyName
} from "../src/index.mjs";

// Test 1: isValidIdentifier returns true for standard identifier names including alphanumeric characters, dollar signs, and underscores
{
  assert.equal(t.isValidIdentifier("foo"), true);
  assert.equal(t.isValidIdentifier("$bar"), true);
  assert.equal(t.isValidIdentifier("_baz123"), true);
  assert.equal(t.isValidIdentifier("camelCaseVar"), true);
  assert.equal(isAllowedIdentifier("myVar"), true);
  assert.equal(checkValidIdentifier("$test_1", true), true);
}

// Test 2: isValidIdentifier returns false for JavaScript reserved words and keywords when reserved check is enabled by default
{
  assert.equal(t.isValidIdentifier("const"), false);
  assert.equal(t.isValidIdentifier("class"), false);
  assert.equal(t.isValidIdentifier("function"), false);
  assert.equal(t.isValidIdentifier("import"), false);
  assert.equal(t.isValidIdentifier("export"), false);
  assert.equal(t.isValidIdentifier("await"), false);
  assert.equal(t.isValidIdentifier("default"), false);
  assert.equal(isAllowedIdentifier("const"), false);
  assert.equal(checkValidIdentifier("class", true), false);
}

// Test 3: isValidIdentifier returns true for reserved words and keywords when reserved check is set to false
{
  assert.equal(t.isValidIdentifier("const", false), true);
  assert.equal(t.isValidIdentifier("class", false), true);
  assert.equal(t.isValidIdentifier("function", false), true);
  assert.equal(t.isValidIdentifier("default", false), true);
  assert.equal(isAllowedPropertyName("import"), true);
  assert.equal(checkValidIdentifier("export", false), true);
}

// Test 4: isValidIdentifier returns false for strings with invalid identifier characters, digits at start, empty strings, or non-string inputs
{
  assert.equal(t.isValidIdentifier("123foo"), false);
  assert.equal(t.isValidIdentifier("123foo", false), false);
  assert.equal(t.isValidIdentifier("foo-bar"), false);
  assert.equal(t.isValidIdentifier("foo.bar"), false);
  assert.equal(t.isValidIdentifier("foo bar"), false);
  assert.equal(t.isValidIdentifier(""), false);
  assert.equal(t.isValidIdentifier(null), false);
  assert.equal(t.isValidIdentifier(undefined), false);
  assert.equal(t.isValidIdentifier(42), false);
  assert.equal(t.isValidIdentifier({}), false);
  assert.equal(isAllowedIdentifier("foo-bar"), false);
  assert.equal(checkValidIdentifier("", false), false);
}

console.log("All @babel/types.isValidIdentifier contract tests passed successfully.");