[JS/TS] Generate comments for members in class decorated with [<AttachMembers>] (#4403)

MangelMaxime · web-flow · commit 364c5bca55e3 · 2026-03-18T22:41:00.000+01:00
diff --git a/src/Fable.Cli/CHANGELOG.md b/src/Fable.Cli/CHANGELOG.md
@@ -16,6 +16,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 * [Beam] Fix "no effect" warning for pure BIF calls (`self/0`, `node/0`) in non-final block positions (by @dbrattli)
 * [Beam] Fix `reraise()` generating unbound `MatchValue` variable — use raw Erlang reason variable for re-throw (by @dbrattli)
 * [Beam] Fix `Erlang.receive<'T>()` resolving to timeout overload due to F# unit argument (by @dbrattli)
+* [JS/TS] Generate comments for members in class decorated with `[<AttachMembers>]` (by @MangelMaxime)
 * [Beam] Fix `[<ImportAll>]` generating invalid `module:*()` Erlang code when binding is used as a value (by @dbrattli)
 * [Beam] Fix string slicing and `Substring` with compound expressions producing wrong `binary:part` length due to missing parentheses in emitted Erlang (by @dbrattli)
 * [Beam] Fix non-ASCII characters in string literals being truncated to single bytes — emit `<<"..."/utf8>>` instead of `<<"...">>` (by @dbrattli)
diff --git a/src/Fable.Compiler/CHANGELOG.md b/src/Fable.Compiler/CHANGELOG.md
@@ -16,6 +16,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 * [Beam] Fix "no effect" warning for pure BIF calls (`self/0`, `node/0`) in non-final block positions (by @dbrattli)
 * [Beam] Fix `reraise()` generating unbound `MatchValue` variable — use raw Erlang reason variable for re-throw (by @dbrattli)
 * [Beam] Fix `Erlang.receive<'T>()` resolving to timeout overload due to F# unit argument (by @dbrattli)
+* [JS/TS] Generate comments for members in class decorated with `[<AttachMembers>]` (by @MangelMaxime)
 * [Beam] Fix `[<ImportAll>]` generating invalid `module:*()` Erlang code when binding is used as a value (by @dbrattli)
 * [Beam] Fix string slicing and `Substring` with compound expressions producing wrong `binary:part` length due to missing parentheses in emitted Erlang (by @dbrattli)
 * [Beam] Fix non-ASCII characters in string literals being truncated to single bytes — emit `<<"..."/utf8>>` instead of `<<"...">>` (by @dbrattli)
diff --git a/src/Fable.Transforms/Fable2Babel.fs b/src/Fable.Transforms/Fable2Babel.fs
@@ -3379,7 +3379,8 @@ but thanks to the optimisation done below we get
                 ?isAbstract = isAbstract,
                 ?superClass = superClass,
                 typeParameters = typeParameters,
-                implements = implements
+                implements = implements,
+                ?doc = info.JsDoc
             )
         | FunctionExpression(_, parameters, body, returnType, typeParameters, _) ->
             Declaration.functionDeclaration (
@@ -3427,6 +3428,7 @@ but thanks to the optimisation done below we get
         ctx
         (ent: Fable.Entity)
         entName
+        (doc: string option)
         (consArgs: Parameter[])
         (consArgsModifiers: AccessModifier[])
         (consBody: BlockStatement)
@@ -3511,15 +3513,25 @@ but thanks to the optimisation done below we get
                 ?implements = implements
             )
 
-        ModuleDecl(entName, isPublic = ent.IsPublic)
+        ModuleDecl(entName, isPublic = ent.IsPublic, ?doc = doc)
         |> declareModuleMember com ctx classExpr
 
-    let declareClass (com: IBabelCompiler) ctx ent entName consArgs consBody superClass classMembers =
+    let declareClass
+        (com: IBabelCompiler)
+        ctx
+        (ent: Fable.Entity)
+        entName
+        doc
+        consArgs
+        consBody
+        superClass
+        classMembers
+        =
         if com.IsTypeScript then
             FSharp2Fable.Util.getEntityGenArgs ent |> makeTypeParamDecl com ctx |> Some
         else
             None
-        |> declareClassWithParams com ctx ent entName consArgs [||] consBody superClass classMembers
+        |> declareClassWithParams com ctx ent entName doc consArgs [||] consBody superClass classMembers
 
     let declareTypeReflection (com: IBabelCompiler) ctx (ent: Fable.Entity) entName : ModuleDeclaration =
         let ta =
@@ -3549,14 +3561,15 @@ but thanks to the optimisation done below we get
         ctx
         (ent: Fable.Entity)
         entName
+        doc
         (consArgs: Parameter[])
         (consBody: BlockStatement)
         baseExpr
         classMembers
         : ModuleDeclaration list
         =
         let typeDeclaration =
-            declareClass com ctx ent entName consArgs consBody baseExpr classMembers
+            declareClass com ctx ent entName doc consArgs consBody baseExpr classMembers
 
         if com.Options.NoReflection then
             [ typeDeclaration ]
@@ -3710,7 +3723,14 @@ but thanks to the optimisation done below we get
                 yield makeMethod "Symbol.iterator" [||] (enumerableThisToIterator com ctx) returnType None
         |]
 
-    let transformUnion (com: IBabelCompiler) ctx (ent: Fable.Entity) (entName: string) classMembers =
+    let transformUnion
+        (com: IBabelCompiler)
+        ctx
+        (ent: Fable.Entity)
+        (entName: string)
+        (doc: string option)
+        classMembers
+        =
         let isPublic = ent.IsPublic
         let tagArgName = "Tag"
         let tagArgTa = makeAliasTypeAnnotation com ctx tagArgName
@@ -3798,6 +3818,7 @@ but thanks to the optimisation done below we get
                 ctx
                 ent
                 entName
+                doc
                 args
                 consBody
                 baseExpr
@@ -3948,6 +3969,7 @@ but thanks to the optimisation done below we get
                     ctx
                     ent
                     union_cons.Name
+                    doc
                     consArgs
                     consArgsModifiers
                     consBody
@@ -3976,7 +3998,7 @@ but thanks to the optimisation done below we get
                     |]
 
             let classMembers = Array.append [| cases |] classMembers
-            declareType com ctx ent entName args body baseExpr classMembers
+            declareType com ctx ent entName doc args body baseExpr classMembers
 
     let transformClassWithCompilerGeneratedConstructor
         (com: IBabelCompiler)
@@ -4021,7 +4043,7 @@ but thanks to the optimisation done below we get
                 Parameter.parameter (fi.Name, ?typeAnnotation = makeFieldAnnotationIfTypeScript com ctx fi.Type)
             )
 
-        declareType com ctx ent decl.Name args body baseExpr classMembers
+        declareType com ctx ent decl.Name decl.XmlDoc args body baseExpr classMembers
 
     let transformPojoDefinedByConsArgsToInterface
         (com: IBabelCompiler)
@@ -4319,7 +4341,7 @@ but thanks to the optimisation done below we get
             |> Option.defaultValue (None, consBody)
 
         [
-            yield! declareType com ctx ent classDecl.Name consArgs consBody baseExpr classMembers
+            yield! declareType com ctx ent classDecl.Name classDecl.XmlDoc consArgs consBody baseExpr classMembers
 
             if not ent.IsAbstractClass then
                 yield
@@ -4519,7 +4541,7 @@ but thanks to the optimisation done below we get
                         <| fun ctx -> transformClassWithPrimaryConstructor com ctx ent decl classMembers cons
                     | None ->
                         if ent.IsFSharpUnion then
-                            transformUnion com ctx ent decl.Name classMembers
+                            transformUnion com ctx ent decl.Name decl.XmlDoc classMembers
                         else
                             transformClassWithCompilerGeneratedConstructor com ctx ent decl classMembers
 
diff --git a/tests/Integration/Integration/data/xmlComment/ClassMember.fs b/tests/Integration/Integration/data/xmlComment/ClassMember.fs
@@ -0,0 +1,8 @@
+module ClassMember
+
+/// My superb class with attachments and doc comments
+type ClassWithAttachmentsAndDoc(v: int) =
+    /// Gets the value
+    member _.Value = v
+    /// Returns a greeting
+    member _.Greet(name: string) = $"Hello, {name}! Value is {v}."
diff --git a/tests/Integration/Integration/data/xmlComment/ClassMember.jsx.expected b/tests/Integration/Integration/data/xmlComment/ClassMember.jsx.expected
@@ -0,0 +1,33 @@
+
+import { class_type } from "./fable_modules/fable-library-js.5.0.0-rc.3/Reflection.js";
+
+/**
+ * My superb class with attachments and doc comments
+ */
+export class ClassWithAttachmentsAndDoc {
+    constructor(v) {
+        this.v = (v | 0);
+    }
+}
+
+export function ClassWithAttachmentsAndDoc_$reflection() {
+    return class_type("ClassMember.ClassWithAttachmentsAndDoc", undefined, ClassWithAttachmentsAndDoc);
+}
+
+export function ClassWithAttachmentsAndDoc_$ctor_Z524259A4(v) {
+    return new ClassWithAttachmentsAndDoc(v);
+}
+
+/**
+ * Gets the value
+ */
+export function ClassWithAttachmentsAndDoc__get_Value(_) {
+    return _.v | 0;
+}
+
+/**
+ * Returns a greeting
+ */
+export function ClassWithAttachmentsAndDoc__Greet_Z721C83C5(_, name) {
+    return `Hello, ${name}! Value is ${_.v}.`;
+}
diff --git a/tests/Integration/Integration/data/xmlComment/ClassMemberWithAttachMembers.fs b/tests/Integration/Integration/data/xmlComment/ClassMemberWithAttachMembers.fs
@@ -0,0 +1,11 @@
+module ClassMemberClassMemberWithAttachMembers
+
+open Fable.Core
+
+/// My superb class with attachments and doc comments
+[<Fable.Core.AttachMembers>]
+type ClassWithAttachmentsAndDoc(v: int) =
+    /// Gets the value
+    member _.Value = v
+    /// Returns a greeting
+    member _.Greet(name: string) = $"Hello, {name}! Value is {v}."
diff --git a/tests/Integration/Integration/data/xmlComment/ClassMemberWithAttachMembers.jsx.expected b/tests/Integration/Integration/data/xmlComment/ClassMemberWithAttachMembers.jsx.expected
@@ -0,0 +1,33 @@
+
+import { class_type } from "./fable_modules/fable-library-js.5.0.0-rc.3/Reflection.js";
+
+/**
+ * My superb class with attachments and doc comments
+ */
+export class ClassWithAttachmentsAndDoc {
+    constructor(v) {
+        this.v = (v | 0);
+    }
+    /**
+     * Gets the value
+     */
+    get Value() {
+        const _ = this;
+        return _.v | 0;
+    }
+    /**
+     * Returns a greeting
+     */
+    Greet(name) {
+        const _ = this;
+        return `Hello, ${name}! Value is ${_.v}.`;
+    }
+}
+
+export function ClassWithAttachmentsAndDoc_$reflection() {
+    return class_type("ClassMemberClassMemberWithAttachMembers.ClassWithAttachmentsAndDoc", undefined, ClassWithAttachmentsAndDoc);
+}
+
+export function ClassWithAttachmentsAndDoc_$ctor_Z524259A4(v) {
+    return new ClassWithAttachmentsAndDoc(v);
+}
diff --git a/tests/Integration/Integration/data/xmlComment/xmlComment.fsproj b/tests/Integration/Integration/data/xmlComment/xmlComment.fsproj
@@ -0,0 +1,18 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <TargetFramework>net10.0</TargetFramework>
+    <RollForward>Major</RollForward>
+    <GenerateDocumentationFile>true</GenerateDocumentationFile>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <Compile Include="ClassMember.fs" />
+    <Compile Include="ClassMemberWithAttachMembers.fs" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <PackageReference Include="Fable.Core" Version="4.5.0" />
+  </ItemGroup>
+
+</Project>
