IsolationLevel (#3)

* wip

* fix

* rm commented-out code

* extract to file

* add comments

* docs

* fix

* upd

* test

* upd

* flutter_version

* test

* ?

* blessrng

* blessRNG

* experiment

* up

* ultra bless

* .

* maybe closer

* not bruh

* please

* <>

* 777

* pls

* ultra please

* pls

* hope

* fix

* fix

Author: danylo-safonov-solid

example/lib/main.dart

@@ -9,7 +9,11 @@ Future<Response> fetch(Request _) async {
 
   final client = Client(dbUrl);
   await client.connect();
-  final result = await client.transaction('transaction', transaction);
+  final result = await client.transaction(
+    'transaction',
+    transaction,
+    TransactionOptions(isolationLevel: IsolationLevel.serializable),
+  );
   await client.end();
 
   return Response(result.rows.map(rowToPrettyString).join('\n\n'));

lib/deno_postgres_interop.dart

@@ -2,6 +2,8 @@
 library;
 
 export 'src/client.dart';
+export 'src/isolation_level.dart';
 export 'src/query_client.dart';
 export 'src/query_object_result.dart';
 export 'src/transaction.dart';
+export 'src/transaction_options.dart';

lib/src/isolation_level.dart

@@ -0,0 +1,15 @@
+/// https://www.postgresql.org/docs/current/transaction-iso.html
+enum IsolationLevel {
+  /// [postgresql/Transaction Isolation/Read Committed Isolation Level](https://www.postgresql.org/docs/current/transaction-iso.html#XACT-READ-COMMITTED)
+  readCommitted,
+
+  /// [postgresql/Transaction Isolation/Repeatable Read Isolation Level](https://www.postgresql.org/docs/current/transaction-iso.html#XACT-REPEATABLE-READ)
+  repeatableRead,
+
+  /// [postgresql/Transaction Isolation/Serializable Isolation Level](https://www.postgresql.org/docs/current/transaction-iso.html#XACT-SERIALIZABLE)
+  serializable;
+
+  /// Parses a string containing an [IsolationLevel] literal into its instance.
+  static IsolationLevel parse(String string) =>
+      values.firstWhere((e) => e.name == string);
+}

lib/src/query_client.dart

@@ -3,6 +3,7 @@ import 'dart:js_util';
 
 import 'package:deno_postgres_interop/src/query_object_result.dart';
 import 'package:deno_postgres_interop/src/transaction.dart';
+import 'package:deno_postgres_interop/src/transaction_options.dart';
 import 'package:deno_postgres_interop/src/util.dart';
 
 /// [[email protected]/QueryClient](https://deno.land/x/[email protected]/mod.ts?s=QueryClient).
@@ -18,17 +19,25 @@ extension QueryClientProps on QueryClient {
   Future<void> end() => callFutureMethod(this, 'end');
 
   /// [[email protected]/QueryClient/createTransaction](https://deno.land/x/[email protected]/mod.ts?s=QueryClient#method_createTransaction_0).
-  Transaction createTransaction(String name) =>
-      callMethod(this, 'createTransaction', [name]);
+  Transaction createTransaction(String name, [TransactionOptions? options]) =>
+      callMethod(
+        this,
+        'createTransaction',
+        [
+          name,
+          if (options != null) options,
+        ],
+      );
 
   /// Convinience wrapper for [createTransaction],
   /// [TransactionProps.begin],
   /// and [TransactionProps.commit].
   Future<T> transaction<T>(
     String name,
-    Future<T> Function(Transaction) f,
-  ) async {
-    final transaction = createTransaction(name);
+    Future<T> Function(Transaction) f, [
+    TransactionOptions? options,
+  ]) async {
+    final transaction = createTransaction(name, options);
     await transaction.begin();
     final result = await f(transaction);
     await transaction.commit();

lib/src/transaction_options.dart

@@ -0,0 +1,36 @@
+import 'dart:js_interop';
+import 'dart:js_util';
+
+import 'package:deno_postgres_interop/src/isolation_level.dart';
+
+/// [[email protected]/TransactionOptions](https://deno.land/x/[email protected]/mod.ts?s=TransactionOptions)
+@JS()
+class TransactionOptions {
+  /// [[email protected]/TransactionOptions/snapshot](https://deno.land/x/[email protected]/mod.ts?s=TransactionOptions)
+  external String? get snapshot;
+
+  /// [[email protected]/TransactionOptions/constructor](https://deno.land/x/[email protected]/mod.ts?s=TransactionOptions)
+  factory TransactionOptions({
+    IsolationLevel? isolationLevel,
+    bool? isReadOnly,
+    String? snapshot,
+  }) =>
+      jsify({
+        if (isolationLevel != null) 'isolation_level': isolationLevel.name,
+        if (isReadOnly != null) 'read_only': isReadOnly,
+        if (snapshot != null) 'snapshot': snapshot,
+      }) as TransactionOptions;
+}
+
+/// [[email protected]/TransactionOptions](https://deno.land/x/[email protected]/mod.ts?s=TransactionOptions)
+extension TransactionOptionsProps on TransactionOptions {
+  /// [[email protected]/TransactionOptions/isolation_level](https://deno.land/x/[email protected]/mod.ts?s=TransactionOptions)
+  IsolationLevel? get isolationLevel {
+    final jsProperty = getProperty<String?>(this, 'isolation_level');
+
+    return jsProperty == null ? null : IsolationLevel.parse(jsProperty);
+  }
+
+  /// [[email protected]/TransactionOptions/read_only](https://deno.land/x/[email protected]/mod.ts?s=TransactionOptions)
+  bool? get isReadOnly => getProperty(this, 'read_only');
+}