MongoClient: db function is not an effectful operation like mongodb driver

Author: devmatteini

examples/copy-between-dbs.ts

@@ -16,7 +16,7 @@ type MyType = Schema.Schema.Type<typeof MyType>
 
 const program = Effect.gen(function*(_) {
   const sourceInstance = yield* _(MongoClient.connect("mongodb://localhost:27017"))
-  const sourceDb = yield* _(MongoClient.db(sourceInstance, "source"))
+  const sourceDb = MongoClient.db(sourceInstance, "source")
   const sourceCollection = yield* _(Db.documentCollection(sourceDb, "records"))
   const sourceItems = yield* _(
     DocumentCollection.find(sourceCollection),
@@ -25,7 +25,7 @@ const program = Effect.gen(function*(_) {
   )
 
   const destinationInstance = yield* _(MongoClient.connect("mongodb://localhost:27017"))
-  const destinationDb = yield* _(MongoClient.db(destinationInstance, "destination"))
+  const destinationDb = MongoClient.db(destinationInstance, "destination")
   const destinationCollection = yield* _(Db.collection(destinationDb, "records", MyType))
 
   yield* _(Collection.insertMany(destinationCollection, sourceItems))

examples/elaborate-stream-with-partitioned-errors.ts

@@ -18,7 +18,7 @@ type MyType = Schema.Schema.Type<typeof MyType>
 
 const program = Effect.gen(function*(_) {
   const sourceInstance = yield* _(MongoClient.connect("mongodb://localhost:27017"))
-  const sourceDb = yield* _(MongoClient.db(sourceInstance, "source"))
+  const sourceDb = MongoClient.db(sourceInstance, "source")
   const sourceCollection = yield* _(Db.documentCollection(sourceDb, "records"))
 
   yield* _(

src/Db.ts

@@ -71,7 +71,7 @@ export const fromEffect = <DbK extends string, MongoClientK extends string, E =
       const dbName_ = yield* _(dbName)
       const db = yield* _(
         client,
-        Effect.flatMap((client) => MongoClient.db(client, dbName_)),
+        Effect.map((client) => MongoClient.db(client, dbName_)),
         Effect.cached
       )
       return dbTag.of({ db } as DbService<DbK>) // TODO fix cast using branded ctor

src/MongoClient.ts

@@ -18,11 +18,11 @@ export const connect = (url: string, options?: MongoClientOptions) =>
   )
 
 export const db: {
-  (dbName?: string, options?: DbOptions): (client: MongoClient) => Effect.Effect<Db>
-  (client: MongoClient, dbName?: string, options?: DbOptions): Effect.Effect<Db>
+  (dbName?: string, options?: DbOptions): (client: MongoClient) => Db
+  (client: MongoClient, dbName?: string, options?: DbOptions): Db
 } = F.dual(
   (args) => isMongoClient(args[0]),
-  (client: MongoClient, dbName?: string, options?: DbOptions) => Effect.sync(() => client.db(dbName, options))
+  (client: MongoClient, dbName?: string, options?: DbOptions) => client.db(dbName, options)
 )
 
 const isMongoClient = (x: unknown) => x instanceof MongoClient_