feat(formatter): implement formatting for TSIntersectiontype

crates/oxc_formatter/src/generated/format.rs

@@ -3807,9 +3807,19 @@ impl<'a> Format<'a> for AstNode<'a, TSUnionType<'a>> {
 impl<'a> Format<'a> for AstNode<'a, TSIntersectionType<'a>> {
     fn fmt(&self, f: &mut Formatter<'_, 'a>) -> FormatResult<()> {
         let is_suppressed = f.comments().is_suppressed(self.span().start);
+        if !is_suppressed && format_type_cast_comment_node(self, false, f)? {
+            return Ok(());
+        }
         self.format_leading_comments(f)?;
+        let needs_parentheses = self.needs_parentheses(f);
+        if needs_parentheses {
+            "(".fmt(f)?;
+        }
         let result =
             if is_suppressed { FormatSuppressedNode(self.span()).fmt(f) } else { self.write(f) };
+        if needs_parentheses {
+            ")".fmt(f)?;
+        }
         self.format_trailing_comments(f)?;
         result
     }

crates/oxc_formatter/src/write/intersection_type.rs

@@ -0,0 +1,108 @@
+use oxc_allocator::Vec;
+use oxc_ast::ast::*;
+use oxc_span::GetSpan;
+
+use crate::{
+    format_args,
+    formatter::{FormatResult, Formatter, prelude::*},
+    generated::ast_nodes::{AstNode, AstNodes},
+    parentheses::NeedsParentheses,
+    write,
+    write::FormatWrite,
+};
+
+impl<'a> FormatWrite<'a> for AstNode<'a, TSIntersectionType<'a>> {
+    fn write(&self, f: &mut Formatter<'_, 'a>) -> FormatResult<()> {
+        let types = self.types();
+
+        if types.len() == 1 {
+            return write!(f, self.types().first());
+        }
+
+        let content = format_with(|f| {
+            if self.needs_parentheses(f) {
+                return write!(
+                    f,
+                    [
+                        indent(&format_once(|f| format_intersection_types(types, f))),
+                        soft_line_break()
+                    ]
+                );
+            }
+
+            let is_inside_complex_tuple_type = match self.parent {
+                AstNodes::TSTupleType(tuple) => tuple.element_types().len() > 1,
+                _ => false,
+            };
+
+            if is_inside_complex_tuple_type {
+                write!(
+                    f,
+                    [
+                        indent(&format_args!(
+                            if_group_breaks(&format_args!(text("("), soft_line_break())),
+                            format_once(|f| format_intersection_types(types, f))
+                        )),
+                        soft_line_break(),
+                        if_group_breaks(&text(")"))
+                    ]
+                )
+            } else {
+                format_intersection_types(types, f)
+            }
+        });
+
+        write!(f, [group(&content)])
+    }
+}
+
+/// Check if a TSType is object-like (object literal, mapped type, etc.)
+fn is_object_like_type(ty: &TSType) -> bool {
+    matches!(ty, TSType::TSTypeLiteral(_) | TSType::TSMappedType(_))
+}
+
+// [Prettier applies]: https://github.com/prettier/prettier/blob/cd3e530c2e51fb8296c0fb7738a9afdd3a3a4410/src/language-js/print/type-annotation.js#L93-L120
+fn format_intersection_types<'a>(
+    node: &AstNode<'a, Vec<'a, TSType<'a>>>,
+    f: &mut Formatter<'_, 'a>,
+) -> FormatResult<()> {
+    let last_index = node.len().saturating_sub(1);
+    let mut is_prev_object_like = false;
+    let mut is_chain_indented = false;
+
+    for (index, item) in node.iter().enumerate() {
+        let is_object_like = is_object_like_type(item.as_ref());
+
+        // always inline first element
+        if index == 0 {
+            write!(f, item)?;
+        } else {
+            // If no object is involved, go to the next line if it breaks
+            if !is_prev_object_like && !is_object_like {
+                write!(f, [indent(&format_args!(soft_line_break_or_space(), item))])?;
+            } else {
+                write!(f, space())?;
+
+                if !is_prev_object_like || !is_object_like {
+                    // indent if we move from object to non-object or vice versa, otherwise keep inline
+                    is_chain_indented = index > 1;
+                }
+
+                if is_chain_indented {
+                    write!(f, [indent(&item)])?;
+                } else {
+                    write!(f, item)?;
+                }
+            }
+        }
+
+        // Add separator if not the last element
+        if index < last_index {
+            write!(f, [space(), "&"])?;
+        }
+
+        is_prev_object_like = is_object_like;
+    }
+
+    Ok(())
+}

crates/oxc_formatter/src/write/mod.rs

@@ -13,6 +13,7 @@ mod export_declarations;
 mod function;
 mod import_declaration;
 mod import_expression;
+mod intersection_type;
 mod jsx;
 mod member_expression;
 mod object_like;
@@ -1210,27 +1211,6 @@ impl<'a> FormatWrite<'a> for AstNode<'a, TSConditionalType<'a>> {
     }
 }
 
-impl<'a> FormatWrite<'a> for AstNode<'a, TSIntersectionType<'a>> {
-    fn write(&self, f: &mut Formatter<'_, 'a>) -> FormatResult<()> {
-        let mut types = self.types().iter();
-        let needs_parentheses = self.needs_parentheses(f);
-        if needs_parentheses {
-            write!(f, "(")?;
-        }
-        if let Some(item) = types.next() {
-            write!(f, item)?;
-
-            for item in types {
-                write!(f, [" & ", item])?;
-            }
-        }
-        if needs_parentheses {
-            write!(f, ")")?;
-        }
-        Ok(())
-    }
-}
-
 impl<'a> FormatWrite<'a> for AstNode<'a, TSParenthesizedType<'a>> {
     fn write(&self, f: &mut Formatter<'_, 'a>) -> FormatResult<()> {
         write!(f, ["(", self.type_annotation(), ")"])

tasks/ast_tools/src/generators/formatter/format.rs

@@ -38,7 +38,7 @@ const AST_NODE_WITHOUT_PRINTING_COMMENTS_LIST: &[&str] = &[
 ];
 
 const AST_NODE_NEEDS_PARENTHESES: &[&str] =
-    &["TSTypeAssertion", "TSInferType", "TSConditionalType", "TSUnionType"];
+    &["TSTypeAssertion", "TSInferType", "TSConditionalType", "TSUnionType", "TSIntersectionType"];
 
 const NEEDS_IMPLEMENTING_FMT_WITH_OPTIONS: phf::Map<&'static str, &'static str> = phf::phf_map! {
     "ArrowFunctionExpression" => "FormatJsArrowFunctionExpressionOptions",

tasks/coverage/snapshots/formatter_typescript.snap

@@ -2,7 +2,7 @@ commit: 261630d6
 
 formatter_typescript Summary:
 AST Parsed     : 8816/8816 (100.00%)
-Positive Passed: 8788/8816 (99.68%)
+Positive Passed: 8789/8816 (99.69%)
 Mismatch: tasks/coverage/typescript/tests/cases/compiler/amdLikeInputDeclarationEmit.ts
 
 Expect to Parse: tasks/coverage/typescript/tests/cases/compiler/arrayFromAsync.ts
@@ -15,8 +15,6 @@ Mismatch: tasks/coverage/typescript/tests/cases/compiler/complexNarrowingWithAny
 
 Mismatch: tasks/coverage/typescript/tests/cases/compiler/declarationEmitCastReusesTypeNode4.ts
 
-Mismatch: tasks/coverage/typescript/tests/cases/compiler/declarationEmitRecursiveConditionalAliasPreserved.ts
-
 Mismatch: tasks/coverage/typescript/tests/cases/compiler/declarationEmitShadowingInferNotRenamed.ts
 
 Mismatch: tasks/coverage/typescript/tests/cases/compiler/jsxNamespaceGlobalReexport.tsx

tasks/prettier_conformance/snapshots/prettier.ts.snap.md

@@ -1,4 +1,4 @@
-ts compatibility: 414/573 (72.25%)
+ts compatibility: 417/573 (72.77%)
 
 # Failed
 
@@ -17,9 +17,8 @@ ts compatibility: 414/573 (72.25%)
 | typescript/arrow/16067.ts | 💥💥 | 95.92% |
 | typescript/arrow/comments.ts | 💥✨ | 44.44% |
 | typescript/as/as.ts | 💥 | 89.06% |
-| typescript/as/assignment2.ts | 💥 | 94.12% |
 | typescript/as/expression-statement.ts | 💥 | 75.00% |
-| typescript/assignment/issue-10846.ts | 💥 | 60.00% |
+| typescript/assignment/issue-10846.ts | 💥 | 57.14% |
 | typescript/assignment/issue-10848.tsx | 💥 | 52.12% |
 | typescript/assignment/issue-10850.ts | 💥 | 50.00% |
 | typescript/cast/generic-cast.ts | 💥 | 39.24% |
@@ -91,18 +90,18 @@ ts compatibility: 414/573 (72.25%)
 | typescript/export/export.ts | 💥 | 85.71% |
 | typescript/function-type/consistent.ts | 💥 | 70.83% |
 | typescript/function-type/type-annotation.ts | 💥 | 0.00% |
-| typescript/generic/arrow-return-type.ts | 💥 | 80.00% |
+| typescript/generic/arrow-return-type.ts | 💥 | 79.25% |
 | typescript/generic/issue-6899.ts | 💥 | 21.05% |
 | typescript/generic/object-method.ts | 💥 | 72.73% |
 | typescript/index-signature/static.ts | 💥 | 66.67% |
 | typescript/infer-extends/basic.ts | 💥 | 71.43% |
 | typescript/interface/comments-generic.ts | 💥💥 | 30.00% |
 | typescript/interface/ignore.ts | 💥💥 | 88.26% |
-| typescript/interface/long-type-parameters/long-type-parameters.ts | 💥💥 | 45.00% |
+| typescript/interface/long-type-parameters/long-type-parameters.ts | 💥💥 | 43.05% |
 | typescript/interface2/comments-declare.ts | 💥 | 66.67% |
 | typescript/interface2/comments.ts | 💥 | 78.87% |
 | typescript/interface2/break/break.ts | 💥💥💥 | 80.23% |
-| typescript/intersection/intersection-parens.ts | 💥💥 | 59.14% |
+| typescript/intersection/intersection-parens.ts | 💥💥 | 72.25% |
 | typescript/intersection/type-arguments.ts | 💥💥 | 46.67% |
 | typescript/intersection/consistent-with-flow/intersection-parens.ts | 💥 | 69.77% |
 | typescript/key-remapping-in-mapped-types/key-remapping.ts | 💥 | 23.53% |
@@ -130,7 +129,6 @@ ts compatibility: 414/573 (72.25%)
 | typescript/prettier-ignore/prettier-ignore-parenthesized-type.ts | 💥 | 0.00% |
 | typescript/rest-type/complex.ts | 💥 | 0.00% |
 | typescript/rest-type/infer-type.ts | 💥 | 80.00% |
-| typescript/satisfies-operators/assignment.ts | 💥💥 | 90.91% |
 | typescript/satisfies-operators/expression-statement.ts | 💥💥 | 78.38% |
 | typescript/satisfies-operators/lhs.ts | 💥✨ | 35.00% |
 | typescript/template-literal-types/template-literal-types.ts | 💥 | 80.00% |
@@ -156,7 +154,6 @@ ts compatibility: 414/573 (72.25%)
 | typescript/typeparams/long-function-arg.ts | 💥 | 76.92% |
 | typescript/typeparams/empty-parameters-with-arrow-function/issue-13817.ts | 💥 | 66.67% |
 | typescript/typeparams/trailing-comma/type-paramters.ts | 💥💥💥 | 28.57% |
-| typescript/union/comments.ts | 💥 | 84.21% |
 | typescript/union/inlining.ts | 💥 | 77.37% |
 | typescript/union/union-parens.ts | 💥 | 92.59% |
 | typescript/union/with-type-params.ts | 💥 | 37.50% |