Only enable Node lint rules for Node files

In a previous commit, we mistakenly introduced a Node-specific function
for testing deep equality, and this ended up crashing the extension.
This would usually have been caught by our ESLint rules, as they
prohibit use of Node libraries by default. However, the ESLint
configuration for this repo imports rules from our
`@metamask/eslint-config-nodejs` package and applies them to all files,
marking everything as Node-compatible, thereby allowing such usage. This
is incorrect: these rules should only apply to test files and scripts.

This commit fix the ESLint configuration to match. Doing so revealed a
couple of categories of violations, which this commit also fixes:

- Some packages import and make use of EventEmitter from Node's `events`
  module. We can't assume this exists in a browser context, so we fix
  this by importing the `events` NPM package.
- Some packages import and make use of Node's `assert` module to check
  values at runtime. It isn't strictly necessary to use this module, and
  so we replace its usage with simpler code.

.eslintrc.js

@@ -1,9 +1,9 @@
 module.exports = {
   root: true,
-  extends: ['@metamask/eslint-config', '@metamask/eslint-config-nodejs'],
+  extends: ['@metamask/eslint-config'],
   ignorePatterns: [
     '!.eslintrc.js',
-    '!jest.config.js',
+    '!.prettierrc.js',
     'node_modules',
     '**/dist',
     '**/docs',
@@ -12,6 +12,19 @@ module.exports = {
     'scripts/create-package/package-template',
   ],
   overrides: [
+    {
+      files: [
+        '**/jest.config.js',
+        '**/jest.environment.js',
+        '**/tests/**/*.{ts,js}',
+        '*.js',
+        '*.test.{ts,js}',
+        'scripts/*.ts',
+        'scripts/create-package/*.ts',
+        'tsup.config.ts',
+      ],
+      extends: ['@metamask/eslint-config-nodejs'],
+    },
     {
       files: ['*.test.{ts,js}', '**/tests/**/*.{ts,js}'],
       extends: ['@metamask/eslint-config-jest'],
@@ -121,5 +134,8 @@ module.exports = {
     'import/resolver': {
       typescript: {},
     },
+    jsdoc: {
+      mode: 'typescript',
+    },
   },
 };

packages/message-manager/README.md

@@ -10,6 +10,10 @@ or
 
 `npm install @metamask/message-manager`
 
+## Compatibility
+
+This package relies implicitly upon the `EventEmitter` module. This module is available natively in Node.js, but when using this package for the browser, make sure to use a polyfill such as `events`.
+
 ## Contributing
 
 This package is part of a monorepo. Instructions for contributing can be found in the [monorepo README](https://github.com/MetaMask/core#readme).

packages/message-manager/src/AbstractMessageManager.ts

@@ -1,6 +1,8 @@
 import type { BaseConfig, BaseState } from '@metamask/base-controller';
 import { BaseControllerV1 } from '@metamask/base-controller';
 import type { Hex, Json } from '@metamask/utils';
+// This package purposefully relies on Node's EventEmitter module.
+// eslint-disable-next-line import/no-nodejs-modules
 import { EventEmitter } from 'events';
 
 /**

packages/network-controller/src/NetworkController.ts

@@ -21,7 +21,6 @@ import {
   hasProperty,
   isPlainObject,
 } from '@metamask/utils';
-import { strict as assert } from 'assert';
 import { v4 as random } from 'uuid';
 
 import { INFURA_BLOCKED_KEY, NetworkStatus } from './constants';
@@ -131,7 +130,9 @@ function assertOfType<Type>(
   validate: (value: unknown) => boolean,
   message: string,
 ): asserts value is Type {
-  assert.ok(validate(value), message);
+  if (!validate(value)) {
+    throw new Error(message);
+  }
 }
 
 /**
@@ -878,19 +879,20 @@ export class NetworkController extends BaseController<
    * removed in a future release
    */
   async setProviderType(type: InfuraNetworkType) {
-    assert.notStrictEqual(
-      type,
-      NetworkType.rpc,
-      // TODO: Either fix this lint violation or explain why it's necessary to ignore.
-      // eslint-disable-next-line @typescript-eslint/restrict-template-expressions
-      `NetworkController - cannot call "setProviderType" with type "${NetworkType.rpc}". Use "setActiveNetwork"`,
-    );
-    assert.ok(
-      isInfuraNetworkType(type),
-      // TODO: Either fix this lint violation or explain why it's necessary to ignore.
-      // eslint-disable-next-line @typescript-eslint/restrict-template-expressions
-      `Unknown Infura provider type "${type}".`,
-    );
+    if ((type as unknown) === NetworkType.rpc) {
+      throw new Error(
+        // TODO: Either fix this lint violation or explain why it's necessary to ignore.
+        // eslint-disable-next-line @typescript-eslint/restrict-template-expressions
+        `NetworkController - cannot call "setProviderType" with type "${NetworkType.rpc}". Use "setActiveNetwork"`,
+      );
+    }
+    if (!isInfuraNetworkType(type)) {
+      throw new Error(
+        // TODO: Either fix this lint violation or explain why it's necessary to ignore.
+        // eslint-disable-next-line @typescript-eslint/restrict-template-expressions
+        `Unknown Infura provider type "${type}".`,
+      );
+    }
 
     await this.setActiveNetwork(type);
   }

packages/signature-controller/README.md

@@ -10,6 +10,10 @@ or
 
 `npm install @metamask/signature-controller`
 
+## Compatibility
+
+This package relies implicitly upon the `EventEmitter` module. This module is available natively in Node.js, but when using this package for the browser, make sure to use a polyfill such as `events`.
+
 ## Contributing
 
 This package is part of a monorepo. Instructions for contributing can be found in the [monorepo README](https://github.com/MetaMask/core#readme).

packages/signature-controller/src/SignatureController.ts

@@ -42,6 +42,8 @@ import {
 } from '@metamask/message-manager';
 import { providerErrors } from '@metamask/rpc-errors';
 import type { Hex, Json } from '@metamask/utils';
+// This package purposefully relies on Node's EventEmitter module.
+// eslint-disable-next-line import/no-nodejs-modules
 import EventEmitter from 'events';
 import { cloneDeep } from 'lodash';
 

packages/transaction-controller/README.md

@@ -10,6 +10,10 @@ or
 
 `npm install @metamask/transaction-controller`
 
+## Compatibility
+
+This package relies implicitly upon the `EventEmitter` module. This module is available natively in Node.js, but when using this package for the browser, make sure to use a polyfill such as `events`.
+
 ## Contributing
 
 This package is part of a monorepo. Instructions for contributing can be found in the [monorepo README](https://github.com/MetaMask/core#readme).

packages/transaction-controller/src/TransactionController.ts

@@ -47,6 +47,8 @@ import type { Hex } from '@metamask/utils';
 import { add0x } from '@metamask/utils';
 import { Mutex } from 'async-mutex';
 import { MethodRegistry } from 'eth-method-registry';
+// This package purposefully relies on Node's EventEmitter module.
+// eslint-disable-next-line import/no-nodejs-modules
 import { EventEmitter } from 'events';
 import { cloneDeep, mapValues, merge, pickBy, sortBy, isEqual } from 'lodash';
 import { v1 as random } from 'uuid';

packages/transaction-controller/src/helpers/GasFeePoller.ts

@@ -6,6 +6,8 @@ import type {
 import type { NetworkClientId, Provider } from '@metamask/network-controller';
 import type { Hex } from '@metamask/utils';
 import { createModuleLogger } from '@metamask/utils';
+// This package purposefully relies on Node's EventEmitter module.
+// eslint-disable-next-line import/no-nodejs-modules
 import EventEmitter from 'events';
 
 import { projectLogger } from '../logger';

packages/transaction-controller/src/helpers/IncomingTransactionHelper.ts

@@ -2,6 +2,8 @@ import type { AccountsController } from '@metamask/accounts-controller';
 import type { BlockTracker } from '@metamask/network-controller';
 import type { Hex } from '@metamask/utils';
 import { Mutex } from 'async-mutex';
+// This package purposefully relies on Node's EventEmitter module.
+// eslint-disable-next-line import/no-nodejs-modules
 import EventEmitter from 'events';
 
 import { incomingTransactionsLogger as log } from '../logger';

packages/transaction-controller/src/helpers/PendingTransactionTracker.ts

@@ -4,6 +4,8 @@ import type {
   BlockTracker,
   NetworkClientId,
 } from '@metamask/network-controller';
+// This package purposefully relies on Node's EventEmitter module.
+// eslint-disable-next-line import/no-nodejs-modules
 import EventEmitter from 'events';
 import { cloneDeep, merge } from 'lodash';
 

packages/user-operation-controller/README.md

@@ -10,6 +10,10 @@ or
 
 `npm install @metamask/user-operation-controller`
 
+## Compatibility
+
+This package relies implicitly upon the `EventEmitter` module. This module is available natively in Node.js, but when using this package for the browser, make sure to use a polyfill such as `events`.
+
 ## Contributing
 
 This package is part of a monorepo. Instructions for contributing can be found in the [monorepo README](https://github.com/MetaMask/core#readme).

packages/user-operation-controller/src/UserOperationController.ts

@@ -25,6 +25,8 @@ import {
   type TransactionType,
 } from '@metamask/transaction-controller';
 import { add0x } from '@metamask/utils';
+// This package purposefully relies on Node's EventEmitter module.
+// eslint-disable-next-line import/no-nodejs-modules
 import EventEmitter from 'events';
 import type { Patch } from 'immer';
 import { cloneDeep } from 'lodash';

packages/user-operation-controller/src/helpers/PendingUserOperationTracker.ts

@@ -4,6 +4,8 @@ import type { NetworkClient, Provider } from '@metamask/network-controller';
 import { BlockTrackerPollingControllerOnly } from '@metamask/polling-controller';
 import type { Json } from '@metamask/utils';
 import { createModuleLogger, type Hex } from '@metamask/utils';
+// This package purposefully relies on Node's EventEmitter module.
+// eslint-disable-next-line import/no-nodejs-modules
 import EventEmitter from 'events';
 
 import { projectLogger } from '../logger';

scripts/create-package/utils.test.ts

@@ -14,6 +14,7 @@ jest.mock('fs', () => ({
     mkdir: jest.fn(),
     readFile: jest.fn(),
     writeFile: jest.fn(),
+    stat: jest.fn(),
   },
 }));
 
@@ -86,7 +87,9 @@ describe('create-package/utils', () => {
         nodeVersions: '>=18.0.0',
       };
 
-      (fs.existsSync as jest.Mock).mockReturnValueOnce(false);
+      (fs.promises.stat as jest.Mock).mockResolvedValueOnce({
+        isDirectory: () => false,
+      });
 
       (fsUtils.readAllFiles as jest.Mock).mockResolvedValueOnce({
         'src/index.ts': 'export default 42;',
@@ -167,7 +170,9 @@ describe('create-package/utils', () => {
         nodeVersions: '20.0.0',
       };
 
-      (fs.existsSync as jest.Mock).mockReturnValueOnce(true);
+      (fs.promises.stat as jest.Mock).mockResolvedValueOnce({
+        isDirectory: () => true,
+      });
 
       await expect(
         finalizeAndWriteData(packageData, monorepoFileData),

scripts/create-package/utils.ts

@@ -1,5 +1,5 @@
 import execa from 'execa';
-import { existsSync, promises as fs } from 'fs';
+import { promises as fs } from 'fs';
 import path from 'path';
 import { format as prettierFormat } from 'prettier';
 import type { Options as PrettierOptions } from 'prettier';
@@ -94,7 +94,7 @@ export async function finalizeAndWriteData(
   monorepoFileData: MonorepoFileData,
 ) {
   const packagePath = path.join(PACKAGES_PATH, packageData.directoryName);
-  if (existsSync(packagePath)) {
+  if ((await fs.stat(packagePath)).isDirectory()) {
     throw new Error(`The package directory already exists: ${packagePath}`);
   }