fix: Remove undefined from optional property types

Resolves #1525

Author: Gerrit0

src/lib/converter/symbols.ts

@@ -21,6 +21,7 @@ import { ConverterEvents } from "./converter-events";
 import { convertIndexSignature } from "./factories/index-signature";
 import { createSignature } from "./factories/signature";
 import { convertJsDocAlias, convertJsDocCallback } from "./jsdoc";
+import { removeUndefined } from "./utils/reflections";
 
 const symbolConverters: {
     [K in ts.SymbolFlags]?: (
@@ -601,6 +602,10 @@ function convertProperty(
         (context.isConvertingTypeNode() ? parameterType : void 0) ??
             context.checker.getTypeOfSymbolAtLocation(symbol, {} as any)
     );
+
+    if (reflection.flags.isOptional) {
+        reflection.type = removeUndefined(reflection.type);
+    }
 }
 
 function convertArrowAsMethod(

src/test/converter/class/specs-with-lump-categories.json

@@ -358,17 +358,8 @@
                     "isOptional": true
                   },
                   "type": {
-                    "type": "union",
-                    "types": [
-                      {
-                        "type": "intrinsic",
-                        "name": "undefined"
-                      },
-                      {
-                        "type": "intrinsic",
-                        "name": "number"
-                      }
-                    ]
+                    "type": "intrinsic",
+                    "name": "number"
                   }
                 }
               ],
@@ -412,17 +403,8 @@
                     "isReadonly": true
                   },
                   "type": {
-                    "type": "union",
-                    "types": [
-                      {
-                        "type": "intrinsic",
-                        "name": "undefined"
-                      },
-                      {
-                        "type": "intrinsic",
-                        "name": "number"
-                      }
-                    ]
+                    "type": "intrinsic",
+                    "name": "number"
                   }
                 }
               ],

src/test/converter/class/specs.json

@@ -358,17 +358,8 @@
                     "isOptional": true
                   },
                   "type": {
-                    "type": "union",
-                    "types": [
-                      {
-                        "type": "intrinsic",
-                        "name": "undefined"
-                      },
-                      {
-                        "type": "intrinsic",
-                        "name": "number"
-                      }
-                    ]
+                    "type": "intrinsic",
+                    "name": "number"
                   }
                 }
               ],
@@ -412,17 +403,8 @@
                     "isReadonly": true
                   },
                   "type": {
-                    "type": "union",
-                    "types": [
-                      {
-                        "type": "intrinsic",
-                        "name": "undefined"
-                      },
-                      {
-                        "type": "intrinsic",
-                        "name": "number"
-                      }
-                    ]
+                    "type": "intrinsic",
+                    "name": "number"
                   }
                 }
               ],