feat: add language version support to formatting options

extra/dart_fmt.d.ts

@@ -3,6 +3,7 @@ export function format(input: string, filename: string, config?: LayoutConfig):
 interface LayoutConfig {
 	line_width?: number;
 	line_ending?: "lf" | "crlf";
+	language_version?: string;
 }
 
 export type InitInput = RequestInfo | URL | Response | BufferSource | WebAssembly.Module;

extra/dart_fmt.js

@@ -70,6 +70,9 @@ export function format(source, filename = "stdin.dart", config = {}) {
 	if (options.line_ending === "crlf") {
 		options.lineEnding = "\r\n";
 	}
+	if(options.language_version) {
+		options.languageVersion = options.language_version;
+	}
 
 	const result = dart_fmt(source, filename, JSON.stringify(options));
 	const err = result[0] === "x";

lib/binding.dart

@@ -5,17 +5,19 @@ import 'package:dart_fmt/dart_fmt.dart';
 class Options {
   final int? pageWidth;
   final String? lineEnding;
+  final String? languageVersion;
 
   Options.fromJson(Map<String, dynamic> json)
       : pageWidth = json['pageWidth'] as int?,
-        lineEnding = json['lineEnding'] as String?;
+        lineEnding = json['lineEnding'] as String?,
+        languageVersion = json['languageVersion'] as String?;
 }
 
 String formatWrapper(String source, String filename, String options) {
   final config = Options.fromJson(jsonDecode(options));
 
   try {
-    return "o${format(source, filename, pageWidth: config.pageWidth, lineEnding: config.lineEnding)}";
+    return "o${format(source, filename, pageWidth: config.pageWidth, lineEnding: config.lineEnding, version: config.languageVersion)}";
   } catch (e) {
     return "x$e";
   }

lib/dart_fmt.dart

@@ -1,7 +1,14 @@
 import 'package:dart_style/dart_style.dart';
+import 'package:pub_semver/pub_semver.dart';
 
 String format(String source, String filename,
-    {int? pageWidth, String? lineEnding}) {
-  final formatter = DartFormatter(pageWidth: pageWidth, lineEnding: lineEnding);
+    {int? pageWidth, String? lineEnding, String? version}) {
+  final languageVersion = version != null
+      ? Version.parse(version)
+      : DartFormatter.latestLanguageVersion;
+  final formatter = DartFormatter(
+      pageWidth: pageWidth,
+      lineEnding: lineEnding,
+      languageVersion: languageVersion);
   return formatter.format(source, uri: filename);
 }

pubspec.yaml

@@ -9,6 +9,7 @@ environment:
 # Add regular dependencies here.
 dependencies:
   dart_style: ^2.3.7
+  pub_semver: ^2.1.4
 
 dev_dependencies:
   lints: ^5.0.0