feat: add --line-length option to melos format command (#689)

* add line-length option for format command

* Make lineLength parameter nullable

* make line-length nullable

* fix cast error

packages/melos/lib/src/command_runner/format.dart

@@ -19,6 +19,10 @@ class FormatCommand extends MelosCommand {
           '[write]              Overwrite formatted files on disk.\n',
       abbr: 'o',
     );
+    argParser.addOption(
+      'line-length',
+      help: 'The line length to format the code to.',
+    );
   }
 
   @override
@@ -32,6 +36,10 @@ class FormatCommand extends MelosCommand {
     final setExitIfChanged = argResults?['set-exit-if-changed'] as bool;
     final output = argResults?['output'] as String?;
     final concurrency = int.parse(argResults!['concurrency'] as String);
+    final lineLength = switch (argResults?['line-length']) {
+      final int length => length,
+      _ => null,
+    };
 
     final melos = Melos(logger: logger, config: config);
 
@@ -41,6 +49,7 @@ class FormatCommand extends MelosCommand {
       concurrency: concurrency,
       setExitIfChanged: setExitIfChanged,
       output: output,
+      lineLength: lineLength,
     );
   }
 }

packages/melos/lib/src/commands/format.dart

@@ -7,6 +7,7 @@ mixin _FormatMixin on _Melos {
     int concurrency = 1,
     bool setExitIfChanged = false,
     String? output,
+    int? lineLength,
   }) async {
     final workspace =
         await createWorkspace(global: global, packageFilters: packageFilters);
@@ -18,6 +19,7 @@ mixin _FormatMixin on _Melos {
       concurrency: concurrency,
       setExitIfChanged: setExitIfChanged,
       output: output,
+      lineLength: lineLength,
     );
   }
 
@@ -27,6 +29,7 @@ mixin _FormatMixin on _Melos {
     required int concurrency,
     required bool setExitIfChanged,
     String? output,
+    int? lineLength,
   }) async {
     final failures = <String, int?>{};
     final pool = Pool(concurrency);
@@ -35,6 +38,7 @@ mixin _FormatMixin on _Melos {
       'format',
       if (setExitIfChanged) '--set-exit-if-changed',
       if (output != null) '--output $output',
+      if (lineLength != null) '--line-length $lineLength',
       '.',
     ];
     final formatArgsString = formatArgs.join(' ');