metamask-extension/test/unit-global/protect-intrinsics.test.js

import 'ses/lockdown';
import '../../app/scripts/lockdown-run';
import '../../app/scripts/lockdown-more';
import { strict as assert } from 'assert';

// These are Agoric inventions, and we don't care about them.
const ignoreList = new Set([
  'Compartment',
  'HandledPromise',
  'StaticModuleRecord',
]);

describe('non-modifiable intrinsics', function () {
  const namedIntrinsics = Reflect.ownKeys(new Compartment().globalThis);

  const globalProperties = new Set(
    [
      // Added to global scope by ses/dist/lockdown.cjs.
      ...namedIntrinsics,

      // TODO: Also include the named platform globals
      // This grabs every enumerable property on globalThis.
      // ...Object.keys(globalThis),
    ].filter((propertyName) => !ignoreList.has(propertyName)),
  );

  globalProperties.forEach((propertyName) => {
    it(`intrinsic globalThis["${propertyName}"]`, function () {
      const descriptor = Reflect.getOwnPropertyDescriptor(
        globalThis,
        propertyName,
      );

      assert.ok(
        descriptor,
        `globalThis["${propertyName}"] should have a descriptor`,
      );

      // As long as Object.isFrozen is the true Object.isFrozen, the object
      // it is called with cannot lie about being frozen.
      const value = globalThis[propertyName];
      if (value !== globalThis) {
        assert.equal(
          Object.isFrozen(value),
          true,
          `value of universal property globalThis["${propertyName}"] should be frozen`,
        );
      }

      // The writability of properties with accessors cannot be modified.
      if ('set' in descriptor || 'get' in descriptor) {
        assert.equal(
          descriptor.configurable,
          false,
          `globalThis["${propertyName}"] should be non-configurable`,
        );
      } else {
        assert.equal(
          descriptor.configurable,
          false,
          `globalThis["${propertyName}"] should be non-configurable`,
        );

        assert.equal(
          descriptor.writable,
          false,
          `globalThis["${propertyName}"] should be non-writable`,
        );
      }
    });
  });
});