feat(pretter): start formatting ModuleDeclaration and ArrowExpression (#1354)

crates/oxc_ast/src/ast/js.rs

@@ -1848,15 +1848,14 @@ impl<'a> ModuleDeclaration<'a> {
         matches!(self, Self::ImportDeclaration(_))
     }
 
+    #[rustfmt::skip]
     pub fn is_export(&self) -> bool {
-        matches!(
-            self,
-            Self::ExportAllDeclaration(_)
-                | Self::ExportDefaultDeclaration(_)
-                | Self::ExportNamedDeclaration(_)
-                | Self::TSExportAssignment(_)
-                | Self::TSNamespaceExportDeclaration(_)
-        )
+        matches!(self, Self::ExportAllDeclaration(_) | Self::ExportDefaultDeclaration(_) | Self::ExportNamedDeclaration(_)
+                | Self::TSExportAssignment(_) | Self::TSNamespaceExportDeclaration(_))
+    }
+
+    pub fn is_default_export(&self) -> bool {
+        matches!(self, Self::ExportDefaultDeclaration(_))
     }
 }
 
@@ -1977,6 +1976,10 @@ impl<'a> ExportNamedDeclaration<'a> {
     }
 }
 
+/// Export Default Declaration
+/// export default HoistableDeclaration
+/// export default ClassDeclaration
+/// export default AssignmentExpression
 #[derive(Debug, Hash)]
 #[cfg_attr(feature = "serde", derive(Serialize), serde(tag = "type"))]
 pub struct ExportDefaultDeclaration<'a> {

crates/oxc_prettier/src/format/arrow_function.rs

@@ -0,0 +1,15 @@
+#[allow(clippy::wildcard_imports)]
+use oxc_ast::ast::*;
+
+use crate::{doc::Doc, ss, Format, Prettier};
+
+impl<'a> Prettier<'a> {
+    pub(super) fn print_arrow_function(&mut self, expr: &ArrowExpression<'a>) -> Doc<'a> {
+        let mut parts = self.vec();
+
+        parts.push(ss!("() => "));
+        parts.push(expr.body.format(self));
+
+        Doc::Array(parts)
+    }
+}

crates/oxc_prettier/src/format/mod.rs

@@ -9,11 +9,13 @@ use oxc_allocator::{Box, Vec};
 #[allow(clippy::wildcard_imports)]
 use oxc_ast::ast::*;
 
+mod arrow_function;
 mod binaryish;
 mod block;
 mod call_expression;
 mod function;
 mod function_parameters;
+mod module;
 mod object;
 mod statement;
 mod ternary;
@@ -341,7 +343,11 @@ impl<'a> Format<'a> for DebuggerStatement {
 
 impl<'a> Format<'a> for ModuleDeclaration<'a> {
     fn format(&self, p: &mut Prettier<'a>) -> Doc<'a> {
-        Doc::Line
+        if let ModuleDeclaration::ImportDeclaration(decl) = self {
+            decl.format(p)
+        } else {
+            p.print_export_declaration(self)
+        }
     }
 }
 
@@ -488,6 +494,18 @@ impl<'a> Format<'a> for ExportNamedDeclaration<'a> {
     }
 }
 
+impl<'a> Format<'a> for TSExportAssignment<'a> {
+    fn format(&self, p: &mut Prettier<'a>) -> Doc<'a> {
+        Doc::Line
+    }
+}
+
+impl<'a> Format<'a> for TSNamespaceExportDeclaration {
+    fn format(&self, p: &mut Prettier<'a>) -> Doc<'a> {
+        Doc::Line
+    }
+}
+
 impl<'a> Format<'a> for ExportSpecifier {
     fn format(&self, p: &mut Prettier<'a>) -> Doc<'a> {
         Doc::Line
@@ -508,12 +526,18 @@ impl<'a> Format<'a> for ExportAllDeclaration<'a> {
 
 impl<'a> Format<'a> for ExportDefaultDeclaration<'a> {
     fn format(&self, p: &mut Prettier<'a>) -> Doc<'a> {
-        Doc::Line
+        self.declaration.format(p)
     }
 }
 impl<'a> Format<'a> for ExportDefaultDeclarationKind<'a> {
     fn format(&self, p: &mut Prettier<'a>) -> Doc<'a> {
-        Doc::Line
+        match self {
+            Self::Expression(expr) => expr.format(p),
+            Self::FunctionDeclaration(decl) => decl.format(p),
+            Self::ClassDeclaration(decl) => decl.format(p),
+            Self::TSInterfaceDeclaration(decl) => decl.format(p),
+            Self::TSEnumDeclaration(decl) => decl.format(p),
+        }
     }
 }
 
@@ -799,7 +823,7 @@ impl<'a> Format<'a> for PropertyKey<'a> {
 
 impl<'a> Format<'a> for ArrowExpression<'a> {
     fn format(&self, p: &mut Prettier<'a>) -> Doc<'a> {
-        Doc::Line
+        p.print_arrow_function(self)
     }
 }
 

crates/oxc_prettier/src/format/module.rs

@@ -0,0 +1,28 @@
+#[allow(clippy::wildcard_imports)]
+use oxc_ast::ast::*;
+
+use crate::{doc::Doc, ss, Format, Prettier};
+
+impl<'a> Prettier<'a> {
+    pub(super) fn print_export_declaration(&mut self, decl: &ModuleDeclaration<'a>) -> Doc<'a> {
+        debug_assert!(decl.is_export());
+
+        let mut parts = self.vec();
+        parts.push(ss!("export"));
+
+        if decl.is_default_export() {
+            parts.push(ss!(" default "));
+        }
+
+        parts.push(match decl {
+            ModuleDeclaration::ImportDeclaration(decl) => unreachable!(),
+            ModuleDeclaration::ExportAllDeclaration(decl) => decl.format(self),
+            ModuleDeclaration::ExportDefaultDeclaration(decl) => decl.format(self),
+            ModuleDeclaration::ExportNamedDeclaration(decl) => decl.format(self),
+            ModuleDeclaration::TSExportAssignment(decl) => decl.format(self),
+            ModuleDeclaration::TSNamespaceExportDeclaration(decl) => decl.format(self),
+        });
+
+        Doc::Array(parts)
+    }
+}

tasks/prettier_conformance/prettier.snap.md

@@ -1,4 +1,4 @@
-Compatibility: 9/173 (5.20%)
+Compatibility: 10/173 (5.78%)
 
 # Failed