fix(NODE-5197): make mdoe enum

Author: durran

src/connection_string.ts

@@ -29,7 +29,7 @@ import {
 } from './mongo_logger';
 import { ReadConcern, type ReadConcernLevel } from './read_concern';
 import { ReadPreference, type ReadPreferenceMode } from './read_preference';
-import { ServerMonitoringModes } from './sdam/monitor';
+import { ServerMonitoringMode } from './sdam/monitor';
 import type { TagSet } from './sdam/server_description';
 import {
   DEFAULT_PK_FACTORY,
@@ -1059,7 +1059,7 @@ export const OPTIONS = {
   serverMonitoringMode: {
     default: 'auto',
     transform({ values: [value] }) {
-      if (!ServerMonitoringModes.includes(value as string)) {
+      if (!Object.values(ServerMonitoringMode).includes(value as any)) {
         throw new MongoParseError(
           'serverMonitoringMode must be one of `auto`, `poll`, or `stream`'
         );

src/index.ts

@@ -490,8 +490,7 @@ export type {
   MonitorPrivate,
   RTTPinger,
   RTTPingerOptions,
-  ServerMonitoringMode,
-  ServerMonitoringModes
+  ServerMonitoringMode
 } from './sdam/monitor';
 export type { Server, ServerEvents, ServerOptions, ServerPrivate } from './sdam/server';
 export type {

src/sdam/monitor.ts

@@ -46,9 +46,14 @@ function isInCloseState(monitor: Monitor) {
 }
 
 /** @public */
-export const ServerMonitoringModes = ['auto', 'poll', 'stream'];
+export const ServerMonitoringMode = Object.freeze({
+  auto: 'auto',
+  poll: 'poll',
+  stream: 'stream'
+} as const);
+
 /** @public */
-export type ServerMonitoringMode = (typeof ServerMonitoringModes)[number];
+export type ServerMonitoringMode = (typeof ServerMonitoringMode)[keyof typeof ServerMonitoringMode];
 
 /** @internal */
 export interface MonitorPrivate {
@@ -230,8 +235,8 @@ function useStreamingProtocol(monitor: Monitor, topologyVersion: TopologyVersion
   if (topologyVersion == null) return false;
 
   const serverMonitoringMode = monitor.options.serverMonitoringMode;
-  if (serverMonitoringMode === 'poll') return false;
-  if (serverMonitoringMode === 'stream') return true;
+  if (serverMonitoringMode === ServerMonitoringMode.poll) return false;
+  if (serverMonitoringMode === ServerMonitoringMode.stream) return true;
 
   // If we are in auto mode, we need to figure out if we're in a FaaS
   // environment or not and choose the appropriate mode.