Const enum recommendation Eslint plugin

change/@microsoft-teams-js-6cae075f-47d3-4274-b35a-bbd901a3082b.json

@@ -0,0 +1,7 @@
+{
+  "type": "patch",
+  "comment": "Added an eslint plugin to recommend the use of const enums when possible",
+  "packageName": "@microsoft/teams-js",
+  "email": "noahdarveau@microsoft.com",
+  "dependentChangeType": "patch"
+}

packages/teams-js/.eslintrc.js

@@ -3,7 +3,7 @@ module.exports = {
   parserOptions: {
     project: './tsconfig.eslint.json',
   },
-  plugins: ['strict-null-checks'],
+  plugins: ['strict-null-checks', 'recommend-const-enums'],
   rules: {
     '@typescript-eslint/interface-name-prefix': 'off',
     '@typescript-eslint/no-namespace': 'off',
@@ -13,5 +13,6 @@ module.exports = {
     ],
     'no-inner-declarations': 'off',
     'strict-null-checks/all': 'warn',
+    'recommend-const-enums/recommend-const-enums': 'warn',
   },
 };

packages/teams-js/eslint-rules/eslint-plugin-recommend-const-enums/index.js

@@ -0,0 +1,4 @@
+const recommendConstEnumsRule = require('./recommendConstEnums.js');
+
+const plugin = { rules: { 'recommend-const-enums': recommendConstEnumsRule } };
+module.exports = plugin;

packages/teams-js/eslint-rules/eslint-plugin-recommend-const-enums/package.json

@@ -0,0 +1,16 @@
+{
+  "name": "eslint-plugin-recommend-const-enums",
+  "version": "0.0.0",
+  "license": "MIT",
+  "author": "Noah",
+  "description": "Recommend using const enums",
+  "type": "commonjs",
+  "keywords": [
+    "eslint",
+    "eslint-plugin",
+    "eslintplugin"
+  ],
+  "peerDependencies": {
+    "eslint": ">=5.0.0"
+  }
+}

packages/teams-js/eslint-rules/eslint-plugin-recommend-const-enums/recommendConstEnums.js

@@ -0,0 +1,30 @@
+module.exports = {
+  meta: {
+    type: 'suggestion',
+    docs: {
+      description: 'Recommend using const enums if possible to minimize bundle size',
+      category: 'Best Practices',
+      recommended: true,
+    },
+    fixable: 'code',
+    schema: [],
+  },
+
+  create: function (context) {
+    return {
+      TSEnumDeclaration: function (node) {
+        const enumName = node.id.name;
+        const enumType = node.const ? 'const' : 'regular';
+
+        if (enumType === 'regular') {
+          context.report({
+            node: node,
+            message: `Please consider if you can use a const enum for ${enumName} to minimize bundle size. If not, add "/* eslint-disable-next-line recommend-const-enums/recommend-const-enums */" to the line above to disable this warning, 
+            as well as a comment explaining why you can't use a const enum. To learn more about why we typically want to use const enums, see https://github.com/OfficeDev/microsoft-teams-library-js/wiki/Notes-on-Enum-Usage.`,
+            severity: 2,
+          });
+        }
+      },
+    };
+  },
+};

packages/teams-js/package.json

@@ -25,7 +25,8 @@
     "debug": "^4.3.3"
   },
   "devDependencies": {
-    "@types/debug": "^4.1.7"
+    "@types/debug": "^4.1.7",
+    "eslint-plugin-recommend-const-enums": "file:./eslint-rules/eslint-plugin-recommend-const-enums"
   },
   "license": "MIT",
   "files": [

packages/teams-js/src/private/remoteCamera.ts

@@ -58,6 +58,8 @@ export namespace remoteCamera {
    * @internal
    * Limited to Microsoft-internal use
    */
+  //This enum is not const and the eslint rule is being surpressed because in the teams-test-app, the ControlCommand enum object is being accessed at runtime through the Object.values method.
+  /* eslint-disable-next-line recommend-const-enums/recommend-const-enums */
   export enum ControlCommand {
     Reset = 'Reset',
     ZoomIn = 'ZoomIn',

packages/teams-js/src/public/app.ts

@@ -227,6 +227,9 @@ export namespace app {
   /**
    * Describes errors that caused app initialization to fail
    */
+  /* This enum is not const and the eslint rule is being surpressed because it existed before the PR to make all enums const and is public. 
+  Since it is public, we can not know how clients are using the enum, so if we make it const, it could potentially break their code. */
+  /* eslint-disable-next-line recommend-const-enums/recommend-const-enums */
   export enum FailedReason {
     /**
      * Authentication failed
@@ -246,6 +249,9 @@ export namespace app {
    * Describes expected errors that occurred during an otherwise successful
    * app initialization
    */
+  /* This enum is not const and the eslint rule is being surpressed because it existed before the PR to make all enums const and is public. 
+  Since it is public, we can not know how clients are using the enum, so if we make it const, it could potentially break their code. */
+  /* eslint-disable-next-line recommend-const-enums/recommend-const-enums */
   export enum ExpectedFailureReason {
     /**
      * There was a permission error
@@ -272,6 +278,9 @@ export namespace app {
   /**
    * Represents the failed request sent during a failed app initialization.
    */
+  /* This enum is not const and the eslint rule is being surpressed because it existed before the PR to make all enums const and is public. 
+  Since it is public, we can not know how clients are using the enum, so if we make it const, it could potentially break their code. */
+  /* eslint-disable-next-line recommend-const-enums/recommend-const-enums */
   export interface IFailedRequest {
     /**
      * The reason for the failure
@@ -286,6 +295,9 @@ export namespace app {
   /**
    * Represents the failure request sent during an erroneous app initialization.
    */
+  /* This enum is not const and the eslint rule is being surpressed because it existed before the PR to make all enums const and is public. 
+  Since it is public, we can not know how clients are using the enum, so if we make it const, it could potentially break their code. */
+  /* eslint-disable-next-line recommend-const-enums/recommend-const-enums */
   export interface IExpectedFailureRequest {
     /**
      * The reason for the failure

packages/teams-js/src/public/authentication.ts

@@ -767,6 +767,9 @@ export namespace authentication {
    * @internal
    * Limited to Microsoft-internal use
    */
+  /* This enum is not const and the eslint rule is being surpressed because it existed before the PR to make all enums const and is public. 
+  Since it is public, we can not know how clients are using the enum, so if we make it const, it could potentially break their code. */
+  /* eslint-disable-next-line recommend-const-enums/recommend-const-enums */
   export enum DataResidency {
     /**
      * Public

packages/teams-js/src/public/call.ts

@@ -16,6 +16,9 @@ const callTelemetryVersionNumber: ApiVersionNumber = ApiVersionNumber.V_2;
  */
 export namespace call {
   /** Modalities that can be associated with a call. */
+  /* This enum is not const and the eslint rule is being surpressed because it existed before the PR to make all enums const and is public. 
+  Since it is public, we can not know how clients are using the enum, so if we make it const, it could potentially break their code. */
+  /* eslint-disable-next-line recommend-const-enums/recommend-const-enums */
   export enum CallModalities {
     /** Indicates that the modality is unknown or undefined. */
     Unknown = 'unknown',

packages/teams-js/src/public/constants.ts

@@ -1,4 +1,7 @@
 /** HostClientType represents the different client platforms on which host can be run. */
+/* This enum is not const and the eslint rule is being surpressed because it existed before the PR to make all enums const and is public. 
+  Since it is public, we can not know how clients are using the enum, so if we make it const, it could potentially break their code. */
+/* eslint-disable-next-line recommend-const-enums/recommend-const-enums */
 export enum HostClientType {
   /** Represents the desktop client of host, which is installed on a user's computer and runs as a standalone application. */
   desktop = 'desktop',
@@ -30,6 +33,9 @@ export enum HostClientType {
 }
 
 /** HostName indicates the possible hosts for your application. */
+/* This enum is not const and the eslint rule is being surpressed because it existed before the PR to make all enums const and is public. 
+  Since it is public, we can not know how clients are using the enum, so if we make it const, it could potentially break their code. */
+/* eslint-disable-next-line recommend-const-enums/recommend-const-enums */
 export enum HostName {
   /**
    * Office.com and Office Windows App
@@ -78,6 +84,9 @@ export enum HostName {
  * If the app is running in the content context, the developer may want to display information relevant to
  * the content the user is currently viewing.
  */
+/* This enum is not const and the eslint rule is being surpressed because it existed before the PR to make all enums const and is public. 
+  Since it is public, we can not know how clients are using the enum, so if we make it const, it could potentially break their code. */
+/* eslint-disable-next-line recommend-const-enums/recommend-const-enums */
 export enum FrameContexts {
   /**
    * App's frame context from where settings page can be accessed.
@@ -104,6 +113,9 @@ export enum FrameContexts {
  * Indicates the team type, currently used to distinguish between different team
  * types in Office 365 for Education (team types 1, 2, 3, and 4).
  */
+/* This enum is not const and the eslint rule is being surpressed because it existed before the PR to make all enums const and is public. 
+  Since it is public, we can not know how clients are using the enum, so if we make it const, it could potentially break their code. */
+/* eslint-disable-next-line recommend-const-enums/recommend-const-enums */
 export enum TeamType {
   /** Represents a standard or classic team in host that is designed for ongoing collaboration and communication among a group of people. */
   Standard = 0,
@@ -120,6 +132,9 @@ export enum TeamType {
 /**
  * Indicates the various types of roles of a user in a team.
  */
+/* This enum is not const and the eslint rule is being surpressed because it existed before the PR to make all enums const and is public. 
+  Since it is public, we can not know how clients are using the enum, so if we make it const, it could potentially break their code. */
+/* eslint-disable-next-line recommend-const-enums/recommend-const-enums */
 export enum UserTeamRole {
   /** Represents that the user is an owner or administrator of the team. */
   Admin = 0,
@@ -132,6 +147,9 @@ export enum UserTeamRole {
 /**
  * Dialog module dimension enum
  */
+/* This enum is not const and the eslint rule is being surpressed because it existed before the PR to make all enums const and is public. 
+  Since it is public, we can not know how clients are using the enum, so if we make it const, it could potentially break their code. */
+/* eslint-disable-next-line recommend-const-enums/recommend-const-enums */
 export enum DialogDimension {
   /** Represents a large-sized dialog box, which is typically used for displaying large amounts of content or complex workflows that require more space. */
   Large = 'large',
@@ -153,6 +171,9 @@ import { HostVersionsInfo } from './interfaces';
 /**
  * The type of the channel with which the content is associated.
  */
+/* This enum is not const and the eslint rule is being surpressed because it existed before the PR to make all enums const and is public. 
+  Since it is public, we can not know how clients are using the enum, so if we make it const, it could potentially break their code. */
+/* eslint-disable-next-line recommend-const-enums/recommend-const-enums */
 export enum ChannelType {
   /** The default channel type. Type of channel is used for general collaboration and communication within a team. */
   Regular = 'Regular',

packages/teams-js/src/public/interfaces.ts

@@ -186,6 +186,9 @@ export interface LocaleInfo {
 /**
  * Allowed user file open preferences
  */
+/* This enum is not const and the eslint rule is being surpressed because it existed before the PR to make all enums const and is public. 
+  Since it is public, we can not know how clients are using the enum, so if we make it const, it could potentially break their code. */
+/* eslint-disable-next-line recommend-const-enums/recommend-const-enums */
 export enum FileOpenPreference {
   /** Indicates that the user should be prompted to open the file in inline. */
   Inline = 'inline',
@@ -200,6 +203,9 @@ export enum FileOpenPreference {
  *
  * @beta
  */
+/* This enum is not const and the eslint rule is being surpressed because it existed before the PR to make all enums const and is public. 
+  Since it is public, we can not know how clients are using the enum, so if we make it const, it could potentially break their code. */
+/* eslint-disable-next-line recommend-const-enums/recommend-const-enums */
 export enum ActionObjectType {
   /** Represents content within a Microsoft 365 application. */
   M365Content = 'm365content',
@@ -250,6 +256,9 @@ export interface SecondaryId {
  * See [commonly accessed resources](https://learn.microsoft.com/graph/api/resources/onedrive?view=graph-rest-1.0#commonly-accessed-resources).
  * @beta
  */
+/* This enum is not const and the eslint rule is being surpressed because it existed before the PR to make all enums const and is public. 
+  Since it is public, we can not know how clients are using the enum, so if we make it const, it could potentially break their code. */
+/* eslint-disable-next-line recommend-const-enums/recommend-const-enums */
 export enum SecondaryM365ContentIdName {
   /** OneDrive ID */
   DriveId = 'driveId',
@@ -990,6 +999,9 @@ export function isSdkError(err: unknown): err is SdkError {
 }
 
 /** Error codes used to identify different types of errors that can occur while developing apps. */
+/* This enum is not const and the eslint rule is being surpressed because it existed before the PR to make all enums const and is public. 
+  Since it is public, we can not know how clients are using the enum, so if we make it const, it could potentially break their code. */
+/* eslint-disable-next-line recommend-const-enums/recommend-const-enums */
 export enum ErrorCode {
   /**
    * API not supported in the current platform.
@@ -1054,6 +1066,9 @@ export enum ErrorCode {
 }
 
 /** @hidden */
+/* This enum is not const and the eslint rule is being surpressed because it existed before the PR to make all enums const and is public. 
+  Since it is public, we can not know how clients are using the enum, so if we make it const, it could potentially break their code. */
+/* eslint-disable-next-line recommend-const-enums/recommend-const-enums */
 export enum DevicePermission {
   GeoLocation = 'geolocation',
   Media = 'media',
@@ -1077,6 +1092,9 @@ export interface AdaptiveCardVersion {
 /**
  * Currently supported Mime type
  */
+/* This enum is not const and the eslint rule is being surpressed because it existed before the PR to make all enums const and is public. 
+  Since it is public, we can not know how clients are using the enum, so if we make it const, it could potentially break their code. */
+/* eslint-disable-next-line recommend-const-enums/recommend-const-enums */
 export enum ClipboardSupportedMimeType {
   TextPlain = 'text/plain',
   TextHtml = 'text/html',

packages/teams-js/src/public/liveShareHost.ts

@@ -22,6 +22,9 @@ export namespace liveShare {
    * Used in Live Share for its role verification feature.
    * For more information, visit https://learn.microsoft.com/microsoftteams/platform/apps-in-teams-meetings/teams-live-share-capabilities?tabs=javascript#role-verification-for-live-data-structures
    */
+  /* This enum is not const and the eslint rule is being surpressed because it existed before the PR to make all enums const and is public. 
+  Since it is public, we can not know how clients are using the enum, so if we make it const, it could potentially break their code. */
+  /* eslint-disable-next-line recommend-const-enums/recommend-const-enums */
   export enum UserMeetingRole {
     /**
      * Guest role.
@@ -46,6 +49,9 @@ export namespace liveShare {
    * State of the current Live Share session's Fluid container.
    * This is used internally by the `LiveShareClient` when joining a Live Share session.
    */
+  /* This enum is not const and the eslint rule is being surpressed because it existed before the PR to make all enums const and is public. 
+  Since it is public, we can not know how clients are using the enum, so if we make it const, it could potentially break their code. */
+  /* eslint-disable-next-line recommend-const-enums/recommend-const-enums */
   export enum ContainerState {
     /**
      * The call to `LiveShareHost.setContainerId()` successfully created the container mapping

packages/teams-js/src/public/mail.ts

@@ -79,6 +79,9 @@ export namespace mail {
   }
 
   /** Defines compose mail types. */
+  /* This enum is not const and the eslint rule is being surpressed because it existed before the PR to make all enums const and is public. 
+  Since it is public, we can not know how clients are using the enum, so if we make it const, it could potentially break their code. */
+  /* eslint-disable-next-line recommend-const-enums/recommend-const-enums */
   export enum ComposeMailType {
     /** Compose a new mail message. */
     New = 'new',

packages/teams-js/src/public/marketplace.ts

@@ -203,6 +203,9 @@ export namespace marketplace {
    * Represents the persona creating the cart.
    * @beta
    */
+  /* This enum is not const and the eslint rule is being surpressed because it existed before the PR to make all enums const and is public. 
+  Since it is public, we can not know how clients are using the enum, so if we make it const, it could potentially break their code. */
+  /* eslint-disable-next-line recommend-const-enums/recommend-const-enums */
   export enum Intent {
     /**
      * @hidden
@@ -226,6 +229,9 @@ export namespace marketplace {
    * Represents the status of the cart.
    * @beta
    */
+  /* This enum is not const and the eslint rule is being surpressed because it existed before the PR to make all enums const and is public. 
+  Since it is public, we can not know how clients are using the enum, so if we make it const, it could potentially break their code. */
+  /* eslint-disable-next-line recommend-const-enums/recommend-const-enums */
   export enum CartStatus {
     /**
      * @hidden