refactor(ast): introduce #[estree(ts_alias)] attr and use it on Elision

crates/oxc_ast/src/ast/js.rs

@@ -281,7 +281,6 @@ pub struct ThisExpression {
 #[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 pub struct ArrayExpression<'a> {
     pub span: Span,
-    #[estree(ts_type = "Array<SpreadElement | Expression | null>")]
     pub elements: Vec<'a, ArrayExpressionElement<'a>>,
     /// Array trailing comma
     /// <https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Trailing_commas#arrays>
@@ -298,7 +297,6 @@ inherit_variants! {
 #[ast(visit)]
 #[derive(Debug)]
 #[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
-#[estree(no_ts_def)]
 pub enum ArrayExpressionElement<'a> {
     /// `...[3, 4]` in `const array = [1, 2, ...[3, 4], null];`
     SpreadElement(Box<'a, SpreadElement<'a>>) = 64,
@@ -318,7 +316,8 @@ pub enum ArrayExpressionElement<'a> {
 /// Serialized as `null` in JSON AST. See `serialize.rs`.
 #[ast(visit)]
 #[derive(Debug, Clone)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq)]
+#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[estree(custom_serialize, ts_alias = "null")]
 pub struct Elision {
     pub span: Span,
 }

npm/oxc-types/types.d.ts

@@ -77,9 +77,11 @@ export interface ThisExpression extends Span {
 
 export interface ArrayExpression extends Span {
   type: 'ArrayExpression';
-  elements: Array<SpreadElement | Expression | null>;
+  elements: Array<ArrayExpressionElement>;
 }
 
+export type ArrayExpressionElement = SpreadElement | null | Expression;
+
 export interface ObjectExpression extends Span {
   type: 'ObjectExpression';
   properties: Array<ObjectPropertyKind>;

tasks/ast_tools/src/derives/estree.rs

@@ -115,9 +115,8 @@ fn parse_estree_attr(location: AttrLocation, part: AttrPart) -> Result<()> {
             AttrPart::String("custom_ts_def", value) => {
                 struct_def.estree.custom_ts_def = Some(value);
             }
-            AttrPart::String("add_ts_def", value) => {
-                struct_def.estree.add_ts_def = Some(value);
-            }
+            AttrPart::String("ts_alias", value) => struct_def.estree.ts_alias = Some(value),
+            AttrPart::String("add_ts_def", value) => struct_def.estree.add_ts_def = Some(value),
             AttrPart::String("rename", value) => struct_def.estree.rename = Some(value),
             AttrPart::String("via", value) => struct_def.estree.via = Some(value),
             _ => return Err(()),

tasks/ast_tools/src/generators/typescript.rs

@@ -108,6 +108,11 @@ fn generate_ts_type_def(type_def: &TypeDef, code: &mut String, schema: &Schema)
 
 /// Generate Typescript type definition for a struct.
 fn generate_ts_type_def_for_struct(struct_def: &StructDef, schema: &Schema) -> Option<String> {
+    // If struct marked with `#[estree(ts_alias = "...")]`, then it needs no type def
+    if struct_def.estree.ts_alias.is_some() {
+        return None;
+    }
+
     // If struct is marked as `#[estree(flatten)]`, and only has a single field which isn't skipped,
     // don't generate a type def. That single field will be inserted inline into structs which include
     // this one rather than them extending this type.
@@ -252,7 +257,13 @@ fn generate_ts_type_def_for_enum(enum_def: &EnumDef, schema: &Schema) -> String
 /// Get TS type name for a type.
 fn ts_type_name<'s>(type_def: &'s TypeDef, schema: &'s Schema) -> Cow<'s, str> {
     match type_def {
-        TypeDef::Struct(struct_def) => Cow::Borrowed(struct_def.name()),
+        TypeDef::Struct(struct_def) => {
+            if let Some(ts_alias) = &struct_def.estree.ts_alias {
+                Cow::Borrowed(ts_alias)
+            } else {
+                Cow::Borrowed(struct_def.name())
+            }
+        }
         TypeDef::Enum(enum_def) => Cow::Borrowed(enum_def.name()),
         TypeDef::Primitive(primitive_def) => Cow::Borrowed(match primitive_def.name() {
             #[rustfmt::skip]

tasks/ast_tools/src/schema/extensions/estree.rs

@@ -16,6 +16,10 @@ pub struct ESTreeStruct {
     /// Custom TS type definition. Does not include `export`.
     /// Empty string if type should not have a TS type definition.
     pub custom_ts_def: Option<String>,
+    /// TS alias.
+    /// e.g. `#[estree(ts_alias = "null")]` means this type won't have a type def generated,
+    /// and any struct / enum referencing it will substitute `null` as the type.
+    pub ts_alias: Option<String>,
     /// Additional custom TS type definition to add along with the generated one.
     /// Does not include `export`.
     pub add_ts_def: Option<String>,