From 23bde9a2687686a8e49cd7d9579444c04a51c60f Mon Sep 17 00:00:00 2001
From: Gerrit Birkeland <gerrit@gerritbirkeland.com>
Date: Sat, 30 Jul 2022 07:14:34 -0600
Subject: [PATCH] Add support for comments on parameters

Resolves #2019.
---
 CHANGELOG.md                             |  5 +++++
 src/lib/converter/comments/discovery.ts  |  2 ++
 src/lib/converter/factories/signature.ts | 10 +++++++++-
 src/test/converter2/issues/gh2019.ts     |  8 ++++++++
 src/test/issueTests.ts                   | 17 +++++++++++++++++
 5 files changed, 41 insertions(+), 1 deletion(-)
 create mode 100644 src/test/converter2/issues/gh2019.ts

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 0c187ffb5..5ba178ca5 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,10 @@
 # Unreleased
 
+### Features
+
+-   Added support for detecting comments directly before parameters as the parameter comment, #2019.
+-   Added support for using the comment directly before a constructor parameter that declares a property as the property comment, #2019.
+
 ### Bug Fixes
 
 -   Fixed schema URL for TSDoc preventing the use of `typedoc/tsdoc.json` in TSDoc extends, #2015.
diff --git a/src/lib/converter/comments/discovery.ts b/src/lib/converter/comments/discovery.ts
index 373ff5ad5..d81032075 100644
--- a/src/lib/converter/comments/discovery.ts
+++ b/src/lib/converter/comments/discovery.ts
@@ -52,6 +52,8 @@ const wantedKinds: Record<ReflectionKind, ts.SyntaxKind[]> = {
         ts.SyntaxKind.PropertySignature,
         ts.SyntaxKind.BinaryExpression,
         ts.SyntaxKind.PropertyAssignment,
+        // class X { constructor(/** Comment */ readonly z: any) }
+        ts.SyntaxKind.Parameter,
     ],
     [ReflectionKind.Method]: [
         ts.SyntaxKind.FunctionDeclaration,
diff --git a/src/lib/converter/factories/signature.ts b/src/lib/converter/factories/signature.ts
index 00aefd594..2b6709182 100644
--- a/src/lib/converter/factories/signature.ts
+++ b/src/lib/converter/factories/signature.ts
@@ -16,7 +16,7 @@ import type { Context } from "../context";
 import { ConverterEvents } from "../converter-events";
 import { convertDefaultValue } from "../convert-expression";
 import { removeUndefined } from "../utils/reflections";
-import { getJsDocComment, getSignatureComment } from "../comments";
+import { getComment, getJsDocComment, getSignatureComment } from "../comments";
 
 export function createSignature(
     context: Context,
@@ -131,6 +131,14 @@ function convertParameters(
                 context.logger
             );
         }
+        paramRefl.comment ||= getComment(
+            param,
+            paramRefl.kind,
+            context.converter.config,
+            context.logger,
+            context.converter.commentStyle
+        );
+
         context.registerReflection(paramRefl, param);
         context.trigger(ConverterEvents.CREATE_PARAMETER, paramRefl);
 
diff --git a/src/test/converter2/issues/gh2019.ts b/src/test/converter2/issues/gh2019.ts
new file mode 100644
index 000000000..a29968632
--- /dev/null
+++ b/src/test/converter2/issues/gh2019.ts
@@ -0,0 +1,8 @@
+export class A {
+    constructor(
+        /**
+         * Param comment
+         */
+        readonly property: string
+    ) {}
+}
diff --git a/src/test/issueTests.ts b/src/test/issueTests.ts
index 0e893f02c..a58432c9b 100644
--- a/src/test/issueTests.ts
+++ b/src/test/issueTests.ts
@@ -679,6 +679,23 @@ export const issueTests: {
         equal(Model.getAlias(), "Model-1");
     },
 
+    gh2019(project) {
+        const param = query(project, "A.constructor").signatures![0]
+            .parameters![0];
+        const prop = query(project, "A.property");
+
+        equal(
+            Comment.combineDisplayParts(param.comment?.summary),
+            "Param comment",
+            "Constructor parameter"
+        );
+        equal(
+            Comment.combineDisplayParts(prop.comment?.summary),
+            "Param comment",
+            "Property"
+        );
+    },
+
     gh2020(project) {
         const opt = query(project, "Options");
         equal(Comment.combineDisplayParts(opt.comment?.summary), "Desc");