@babel/types 7.29.7: memberExpression

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.memberExpression in pkg:npm/%40babel/types@7.29.7
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:npm/%40babel/types@7.29.7
Demonstrate these symbols/APIs:
  - @babel/types.memberExpression

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-babel-types-member-expression",
  "version": "1.0.0",
  "lockfileVersion": 3,
  "requires": true,
  "packages": {
    "": {
      "name": "sample-babel-types-member-expression",
      "version": "1.0.0",
      "license": "MIT-0",
      "dependencies": {
        "@babel/types": "7.29.7"
      }
    },
    "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": "7.29.7",
      "resolved": "https://registry.npmjs.org/@babel/types/-/types-7.29.7.tgz",
      "integrity": "sha512-4zBIxpPzowiZpusoFkyGVwakdRJUyuH5PxQ/PrqghfdFWWasvnCdPfQXHrenDai+gyLARulZjZowCOj6fjT4pA==",
      "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-member-expression",
  "version": "1.0.0",
  "private": true,
  "type": "module",
  "license": "MIT-0",
  "dependencies": {
    "@babel/types": "7.29.7"
  }
}

{
  "schemaVersion": 1,
  "goal": "verify @babel/types.memberExpression in pkg:npm/%40babel/types@7.29.7",
  "kind": "HOW",
  "packages": [
    "pkg:npm/%40babel/types@7.29.7"
  ],
  "symbols": [
    "@babel/types.memberExpression"
  ]
}

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

export function createStaticMemberExpression(objectName, propertyName) {
  return t.memberExpression(t.identifier(objectName), t.identifier(propertyName), false, false);
}

export function createComputedMemberExpression(objectNode, propertyNode) {
  return t.memberExpression(objectNode, propertyNode, true, false);
}

export function createOptionalMemberExpression(objectNode, propertyNode, computed = false) {
  return t.memberExpression(objectNode, propertyNode, computed, true);
}

export function createNestedMemberExpression(chain) {
  return chain.reduce((acc, prop) => {
    if (!acc) return t.identifier(prop);
    return t.memberExpression(acc, t.identifier(prop));
  }, null);
}

export function checkIsMemberExpression(node, opts) {
  return t.isMemberExpression(node, opts);
}

export function assertIsMemberExpression(node, opts) {
  t.assertMemberExpression(node, opts);
}

import assert from "node:assert/strict";
import * as t from "@babel/types";
import {
  createStaticMemberExpression,
  createComputedMemberExpression,
  createOptionalMemberExpression,
  createNestedMemberExpression,
  checkIsMemberExpression,
  assertIsMemberExpression
} from "../src/index.mjs";

// Test 1: memberExpression constructs a static MemberExpression AST node with object and property identifiers
{
  const node = createStaticMemberExpression("user", "profile");
  assert.equal(node.type, "MemberExpression");
  assert.equal(node.object.type, "Identifier");
  assert.equal(node.object.name, "user");
  assert.equal(node.property.type, "Identifier");
  assert.equal(node.property.name, "profile");
  assert.equal(node.computed, false);
  assert.equal(node.optional, false);
}

// Test 2: memberExpression constructs a computed MemberExpression AST node when computed is true
{
  const obj = t.identifier("data");
  const prop = t.stringLiteral("key-with-dash");
  const node = createComputedMemberExpression(obj, prop);

  assert.equal(node.type, "MemberExpression");
  assert.equal(node.object.name, "data");
  assert.equal(node.property.type, "StringLiteral");
  assert.equal(node.property.value, "key-with-dash");
  assert.equal(node.computed, true);

  const numProp = t.numericLiteral(0);
  const arrayAccess = t.memberExpression(obj, numProp, true);
  assert.equal(arrayAccess.computed, true);
  assert.equal(arrayAccess.property.type, "NumericLiteral");
  assert.equal(arrayAccess.property.value, 0);
}

// Test 3: memberExpression constructs an optional chaining MemberExpression AST node when optional is true
{
  const obj = t.identifier("user");
  const prop = t.identifier("address");
  const node = createOptionalMemberExpression(obj, prop);

  assert.equal(node.type, "MemberExpression");
  assert.equal(node.object.name, "user");
  assert.equal(node.property.name, "address");
  assert.equal(node.computed, false);
  assert.equal(node.optional, true);

  // Nested member expression: a.b.c
  const nested = createNestedMemberExpression(["a", "b", "c"]);
  assert.equal(nested.type, "MemberExpression");
  assert.equal(nested.property.name, "c");
  assert.equal(nested.object.type, "MemberExpression");
  assert.equal(nested.object.property.name, "b");
  assert.equal(nested.object.object.name, "a");
}

// Test 4: isMemberExpression returns true for MemberExpression nodes and false for other AST nodes or invalid inputs
{
  const memNode = createStaticMemberExpression("obj", "prop");
  const idNode = t.identifier("varName");
  const litNode = t.stringLiteral("value");

  assert.equal(checkIsMemberExpression(memNode), true);
  assert.equal(checkIsMemberExpression(idNode), false);
  assert.equal(checkIsMemberExpression(litNode), false);
  assert.equal(checkIsMemberExpression(null), false);
  assert.equal(checkIsMemberExpression(undefined), false);
  assert.equal(checkIsMemberExpression({}), false);
  assert.equal(checkIsMemberExpression({ type: "Identifier", name: "x" }), false);

  // With opts matching
  assert.equal(checkIsMemberExpression(memNode, { computed: false }), true);
  assert.equal(checkIsMemberExpression(memNode, { computed: true }), false);
}

// Test 5: assertMemberExpression succeeds on valid MemberExpression nodes and throws on mismatched node types
{
  const memNode = createStaticMemberExpression("a", "b");
  const numNode = t.numericLiteral(42);

  assert.doesNotThrow(() => {
    assertIsMemberExpression(memNode);
  });

  assert.doesNotThrow(() => {
    assertIsMemberExpression(memNode, { computed: false });
  });

  assert.throws(() => {
    assertIsMemberExpression(numNode);
  });

  assert.throws(() => {
    assertIsMemberExpression(memNode, { computed: true });
  });

  assert.throws(() => {
    assertIsMemberExpression(null);
  });
}

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