fix: default to empty object when all operation arguments are optional

Author: mdevils

src/schema-to-typescript/common/operation-methods.ts

@@ -44,7 +44,7 @@ import {
 import {attachJsDocComment, extractJsDoc, JsDocRenderConfig, renderJsDoc} from '../../utils/jsdoc';
 import {isJsonMediaType, isWildcardMediaType} from '../../utils/media-types';
 import {applyEntityNameCase} from '../../utils/string-utils';
-import {getUserFreiendlySchemaName, mergeTypes} from '../../utils/type-utils';
+import {getUserFreiendlySchemaName, isAssignableToEmptyObject, mergeTypes} from '../../utils/type-utils';
 import {objectPropertyKey, valueToAstExpression} from '../common';
 import {
     OpenApiClientCustomizableBinaryType,
@@ -620,7 +620,13 @@ export function generateOperationMethods({
             const operationMethod = classMethod(
                 'method',
                 identifier(operationName),
-                argument.properties.length > 0 ? [argument] : [],
+                argument.properties.length > 0
+                    ? [
+                          isAssignableToEmptyObject(argument.typeAnnotation.typeAnnotation)
+                              ? assignmentPattern(argument, objectExpression([]))
+                              : argument
+                      ]
+                    : [],
                 blockStatement([
                     returnStatement(
                         operationReturn.wrapResultExpression(

src/utils/type-utils.ts

@@ -3,8 +3,11 @@ import {
     isIdentifier,
     isNumericLiteral,
     isStringLiteral,
+    isTSCallSignatureDeclaration,
+    isTSConstructSignatureDeclaration,
     isTSIntersectionType,
     isTSLiteralType,
+    isTSMethodSignature,
     isTSPropertySignature,
     isTSTypeLiteral,
     isTSUnionType,
@@ -273,3 +276,21 @@ export function simplifyIntersectionTypeIfPossible(intersection: TSIntersectionT
     }
     return intersection;
 }
+
+export function isAssignableToEmptyObject(type: TSType): boolean {
+    if (isTSTypeLiteral(type)) {
+        for (const member of type.members) {
+            if (isTSCallSignatureDeclaration(member) || isTSConstructSignatureDeclaration(member)) {
+                return false;
+            } else if ((isTSMethodSignature(member) || isTSPropertySignature(member)) && !member.optional) {
+                return false;
+            }
+        }
+        return true;
+    } else if (isTSIntersectionType(type)) {
+        return type.types.every(isAssignableToEmptyObject);
+    } else if (isTSUnionType(type)) {
+        return type.types.some(isAssignableToEmptyObject);
+    }
+    return false;
+}