refactor!: remove enums in favor of const objects (#2741)

Changes remaining enums to const objects and exports all user relevant
"enums" from index.ts. Enums are frozen to ensure they remain static.
Added a lint rule to prevent further enums.
Corrected mistake in sourcemap emit settings.

NODE-2973

.eslintrc.json

@@ -32,7 +32,15 @@
     "strict": ["error", "global"],
     "promise/no-native": "error",
 
-    "@typescript-eslint/no-explicit-any": "off"
+    "@typescript-eslint/no-explicit-any": "off",
+
+    "no-restricted-syntax": [
+      "error",
+      {
+        "selector": "TSEnumDeclaration",
+        "message": "Don't declare enums"
+      }
+    ]
   },
   "overrides": [{
     "files": ["*.d.ts"],

src/cmap/message_stream.ts

@@ -7,7 +7,8 @@ import {
   decompress,
   uncompressibleCommands,
   Compressor,
-  CompressorName
+  CompressorName,
+  CompressorId
 } from './wire_protocol/compression';
 import type { Document, BSONSerializeOptions } from '../bson';
 import { BufferPool, Callback } from '../utils';
@@ -177,7 +178,7 @@ function processIncomingData(stream: MessageStream, callback: Callback<Buffer>)
   messageHeader.fromCompressed = true;
   messageHeader.opCode = message.readInt32LE(MESSAGE_HEADER_SIZE);
   messageHeader.length = message.readInt32LE(MESSAGE_HEADER_SIZE + 4);
-  const compressorID = message[MESSAGE_HEADER_SIZE + 8];
+  const compressorID: CompressorId = message[MESSAGE_HEADER_SIZE + 8] as CompressorId;
   const compressedBuffer = message.slice(MESSAGE_HEADER_SIZE + 9);
 
   // recalculate based on wrapped opcode

src/cmap/wire_protocol/compression.ts

@@ -5,11 +5,13 @@ import type { OperationDescription } from '../message_stream';
 import { Snappy } from '../../deps';
 
 /** @public */
-export enum Compressor {
-  none = 0,
-  snappy = 1,
-  zlib = 2
-}
+export const Compressor = Object.freeze({
+  none: 0,
+  snappy: 1,
+  zlib: 2
+} as const);
+
+export type CompressorId = typeof Compressor[keyof typeof Compressor];
 
 /** @public */
 export type CompressorName = keyof typeof Compressor;
@@ -59,7 +61,7 @@ export function compress(
 
 // Decompress a message using the given compressor
 export function decompress(
-  compressorID: Compressor,
+  compressorID: CompressorId,
   compressedData: Buffer,
   callback: Callback<Buffer>
 ): void {

src/connection_string.ts

@@ -25,7 +25,7 @@ import {
 } from './mongo_client';
 import { MongoCredentials } from './cmap/auth/mongo_credentials';
 import type { TagSet } from './sdam/server_description';
-import { Logger, LoggerLevel } from './logger';
+import { Logger, LoggerLevelId } from './logger';
 import { PromiseProvider } from './promise_provider';
 import { createAutoEncrypter } from './operations/connect';
 
@@ -713,7 +713,7 @@ export const OPTIONS = {
   loggerLevel: {
     target: 'logger',
     transform({ values: [value] }) {
-      return new Logger('MongoClient', { loggerLevel: value as LoggerLevel });
+      return new Logger('MongoClient', { loggerLevel: value as LoggerLevelId });
     }
   },
   maxIdleTimeMS: {

src/db.ts

@@ -44,8 +44,8 @@ import { RemoveUserOperation, RemoveUserOptions } from './operations/remove_user
 import { RenameOperation, RenameOptions } from './operations/rename';
 import {
   SetProfilingLevelOperation,
-  ProfilingLevel,
-  SetProfilingLevelOptions
+  SetProfilingLevelOptions,
+  ProfilingLevelId
 } from './operations/set_profiling_level';
 import { executeOperation } from './operations/execute_operation';
 import { EvalOperation, EvalOptions } from './operations/eval';
@@ -639,22 +639,22 @@ export class Db {
    * @param options - Optional settings for the command
    * @param callback - An optional callback, a Promise will be returned if none is provided
    */
-  setProfilingLevel(level: ProfilingLevel): Promise<ProfilingLevel>;
-  setProfilingLevel(level: ProfilingLevel, callback: Callback<ProfilingLevel>): void;
+  setProfilingLevel(level: ProfilingLevelId): Promise<ProfilingLevelId>;
+  setProfilingLevel(level: ProfilingLevelId, callback: Callback<ProfilingLevelId>): void;
   setProfilingLevel(
-    level: ProfilingLevel,
+    level: ProfilingLevelId,
     options: SetProfilingLevelOptions
-  ): Promise<ProfilingLevel>;
+  ): Promise<ProfilingLevelId>;
   setProfilingLevel(
-    level: ProfilingLevel,
+    level: ProfilingLevelId,
     options: SetProfilingLevelOptions,
-    callback: Callback<ProfilingLevel>
+    callback: Callback<ProfilingLevelId>
   ): void;
   setProfilingLevel(
-    level: ProfilingLevel,
-    options?: SetProfilingLevelOptions | Callback<ProfilingLevel>,
-    callback?: Callback<ProfilingLevel>
-  ): Promise<ProfilingLevel> | void {
+    level: ProfilingLevelId,
+    options?: SetProfilingLevelOptions | Callback<ProfilingLevelId>,
+    callback?: Callback<ProfilingLevelId>
+  ): Promise<ProfilingLevelId> | void {
     if (typeof options === 'function') (callback = options), (options = {});
 
     return executeOperation(

src/deps.ts

@@ -68,13 +68,16 @@ try {
 } catch {} // eslint-disable-line
 
 /** @public */
-export const enum AutoEncryptionLoggerLevels {
-  FatalError = 0,
-  Error = 1,
-  Warning = 2,
-  Info = 3,
-  Trace = 4
-}
+export const AutoEncryptionLoggerLevel = Object.freeze({
+  FatalError: 0,
+  Error: 1,
+  Warning: 2,
+  Info: 3,
+  Trace: 4
+} as const);
+
+/** @public */
+export type AutoEncryptionLoggerLevelId = typeof AutoEncryptionLoggerLevel[keyof typeof AutoEncryptionLoggerLevel];
 
 /** @public */
 export interface AutoEncryptionOptions {
@@ -146,7 +149,7 @@ export interface AutoEncryptionOptions {
   bypassAutoEncryption?: boolean;
   options?: {
     /** An optional hook to catch logging messages from the underlying encryption engine */
-    logger?: (level: AutoEncryptionLoggerLevels, message: string) => void;
+    logger?: (level: AutoEncryptionLoggerLevelId, message: string) => void;
   };
   extraOptions?: {
     /**

src/index.ts

@@ -73,6 +73,20 @@ export {
   GridFSBucket
 };
 
+// enums
+export { ProfilingLevel } from './operations/set_profiling_level';
+export { ServerType, TopologyType } from './sdam/common';
+export { LoggerLevel } from './logger';
+export { AutoEncryptionLoggerLevel } from './deps';
+export { BatchType } from './bulk/common';
+export { AuthMechanism } from './cmap/auth/defaultAuthProviders';
+export { CURSOR_FLAGS } from './cursor/abstract_cursor';
+export { Compressor } from './cmap/wire_protocol/compression';
+export { ExplainVerbosity } from './explain';
+export { ReadConcernLevel } from './read_concern';
+export { ReadPreferenceMode } from './read_preference';
+
+// type only exports below, these are removed from emitted JS
 export type { AdminPrivate } from './admin';
 export type { Instrumentation } from './apm';
 export type { Document, BSONSerializeOptions } from './bson';
@@ -99,7 +113,7 @@ export type {
   OperationTime,
   ResumeOptions
 } from './change_stream';
-export type { AuthMechanism, AuthMechanismId } from './cmap/auth/defaultAuthProviders';
+export type { AuthMechanismId } from './cmap/auth/defaultAuthProviders';
 export type { MongoCredentials, MongoCredentialsOptions } from './cmap/auth/mongo_credentials';
 export type {
   WriteProtocolMessageType,
@@ -132,20 +146,19 @@ export type {
   MessageStreamOptions
 } from './cmap/message_stream';
 export type { StreamDescription, StreamDescriptionOptions } from './cmap/stream_description';
-export type { CompressorName, Compressor } from './cmap/wire_protocol/compression';
+export type { CompressorName } from './cmap/wire_protocol/compression';
 export type { CollectionPrivate, CollectionOptions } from './collection';
 export type { AggregationCursorOptions } from './cursor/aggregation_cursor';
 export type {
   CursorCloseOptions,
   CursorStreamOptions,
   AbstractCursorOptions,
-  CURSOR_FLAGS,
   CursorFlag
 } from './cursor/abstract_cursor';
 export type { DbPrivate, DbOptions } from './db';
-export type { AutoEncryptionOptions, AutoEncryptionLoggerLevels, AutoEncrypter } from './deps';
+export type { AutoEncryptionOptions, AutoEncryptionLoggerLevelId, AutoEncrypter } from './deps';
 export type { AnyError, ErrorDescription } from './error';
-export type { Explain, ExplainOptions, ExplainVerbosity, ExplainVerbosityLike } from './explain';
+export type { Explain, ExplainOptions, ExplainVerbosityLike } from './explain';
 export type {
   GridFSBucketReadStream,
   GridFSBucketReadStreamOptions,
@@ -159,14 +172,12 @@ export type {
   TFileId,
   GridFSBucketWriteStream
 } from './gridfs-stream/upload';
-export type { LoggerOptions, LoggerFunction, LoggerLevel } from './logger';
+export type { LoggerOptions, LoggerFunction, LoggerLevelId } from './logger';
 export type {
   MongoClientPrivate,
   MongoClientOptions,
   WithSessionCallback,
   PkFactory,
-  LogLevel,
-  LogLevelId,
   Auth,
   DriverInfo,
   MongoOptions,
@@ -221,7 +232,7 @@ export type { ProfilingLevelOptions } from './operations/profiling_level';
 export type { RemoveUserOptions } from './operations/remove_user';
 export type { RenameOptions } from './operations/rename';
 export type { RunCommandOptions } from './operations/run_command';
-export type { ProfilingLevel, SetProfilingLevelOptions } from './operations/set_profiling_level';
+export type { ProfilingLevelId, SetProfilingLevelOptions } from './operations/set_profiling_level';
 export type { CollStatsOptions, DbStatsOptions } from './operations/stats';
 export type {
   UpdateResult,
@@ -230,22 +241,16 @@ export type {
   UpdateStatement
 } from './operations/update';
 export type { ValidateCollectionOptions } from './operations/validate_collection';
-export type {
-  ReadConcern,
-  ReadConcernLike,
-  ReadConcernLevel,
-  ReadConcernLevelId
-} from './read_concern';
+export type { ReadConcern, ReadConcernLike, ReadConcernLevelId } from './read_concern';
 export type {
   ReadPreferenceLike,
   ReadPreferenceModeId,
-  ReadPreferenceMode,
   ReadPreferenceOptions,
   ReadPreferenceLikeOptions,
   ReadPreferenceFromOptions,
   HedgeOptions
 } from './read_preference';
-export type { ClusterTime, ServerType, TimerQueue, TopologyType } from './sdam/common';
+export type { ClusterTime, ServerTypeId, TimerQueue, TopologyTypeId } from './sdam/common';
 export type { TopologyDescriptionChangedEvent } from './sdam/events';
 export type {
   Monitor,
@@ -282,7 +287,7 @@ export type {
   ServerSessionId,
   WithTransactionCallback
 } from './sessions';
-export type { TransactionOptions, Transaction, TxnState } from './transactions';
+export type { TransactionOptions, Transaction, TxnState, TxnStateId } from './transactions';
 export type {
   Callback,
   ClientMetadata,
@@ -298,7 +303,6 @@ export type { InternalAbstractCursorOptions } from './cursor/abstract_cursor';
 export type {
   BulkOperationBase,
   BulkOperationPrivate,
-  BatchType,
   BatchTypeId,
   FindOperators,
   Batch

src/logger.ts

@@ -1,10 +1,10 @@
-import { format as f } from 'util';
+import { format } from 'util';
 import { MongoError } from './error';
 
 // Filters for classes
 const classFilters: any = {};
 let filteredClasses: any = {};
-let level: LoggerLevel;
+let level: LoggerLevelId;
 
 // Save the process id
 const pid = process.pid;
@@ -13,20 +13,27 @@ const pid = process.pid;
 let currentLogger: LoggerFunction = console.warn;
 
 /** @public */
-export enum LoggerLevel {
-  ERROR = 'error',
-  WARN = 'warn',
-  INFO = 'info',
-  DEBUG = 'debug'
-}
+export const LoggerLevel = Object.freeze({
+  ERROR: 'error',
+  WARN: 'warn',
+  INFO: 'info',
+  DEBUG: 'debug',
+  error: 'error',
+  warn: 'warn',
+  info: 'info',
+  debug: 'debug'
+} as const);
+
+/** @public */
+export type LoggerLevelId = typeof LoggerLevel[keyof typeof LoggerLevel];
 
 /** @public */
 export type LoggerFunction = (message?: any, ...optionalParams: any[]) => void;
 
 /** @public */
 export interface LoggerOptions {
   logger?: LoggerFunction;
-  loggerLevel?: LoggerLevel;
+  loggerLevel?: LoggerLevelId;
 }
 
 /**
@@ -76,7 +83,7 @@ export class Logger {
         (Object.keys(filteredClasses).length === 0 && classFilters[this.className]))
     ) {
       const dateTime = new Date().getTime();
-      const msg = f('[%s-%s:%s] %s %s', 'DEBUG', this.className, pid, dateTime, message);
+      const msg = format('[%s-%s:%s] %s %s', 'DEBUG', this.className, pid, dateTime, message);
       const state = {
         type: LoggerLevel.DEBUG,
         message,
@@ -103,7 +110,7 @@ export class Logger {
         (Object.keys(filteredClasses).length === 0 && classFilters[this.className]))
     ) {
       const dateTime = new Date().getTime();
-      const msg = f('[%s-%s:%s] %s %s', 'WARN', this.className, pid, dateTime, message);
+      const msg = format('[%s-%s:%s] %s %s', 'WARN', this.className, pid, dateTime, message);
       const state = {
         type: LoggerLevel.WARN,
         message,
@@ -130,7 +137,7 @@ export class Logger {
         (Object.keys(filteredClasses).length === 0 && classFilters[this.className]))
     ) {
       const dateTime = new Date().getTime();
-      const msg = f('[%s-%s:%s] %s %s', 'INFO', this.className, pid, dateTime, message);
+      const msg = format('[%s-%s:%s] %s %s', 'INFO', this.className, pid, dateTime, message);
       const state = {
         type: LoggerLevel.INFO,
         message,
@@ -157,7 +164,7 @@ export class Logger {
         (Object.keys(filteredClasses).length === 0 && classFilters[this.className]))
     ) {
       const dateTime = new Date().getTime();
-      const msg = f('[%s-%s:%s] %s %s', 'ERROR', this.className, pid, dateTime, message);
+      const msg = format('[%s-%s:%s] %s %s', 'ERROR', this.className, pid, dateTime, message);
       const state = {
         type: LoggerLevel.ERROR,
         message,
@@ -238,7 +245,7 @@ export class Logger {
    *
    * @param newLevel - Set current log level (debug, warn, info, error)
    */
-  static setLevel(newLevel: LoggerLevel): void {
+  static setLevel(newLevel: LoggerLevelId): void {
     if (
       newLevel !== LoggerLevel.INFO &&
       newLevel !== LoggerLevel.ERROR &&