Merge pull request #2226 from microsoftgraph/fix-null-response

Adds autorest directive to prevent null response objects to output streams via ``WriteObject``

Author: timayabi2020

src/readme.graph.md

@@ -428,6 +428,20 @@ directive:
         let errorDetailsRegex = /(ErrorDetails\s*=\s*)(new.*ErrorDetails\(message\).*)/gmi
         $ = $.replace(errorDetailsRegex, '$1await this.GetErrorDetailsAsync((await response)?.Error, responseMessage)');
 
+        // Prevents null response objects to the output stream for scenarios where response is a model type
+        let responseTypeRegex = /global::System.Threading.Tasks.Task<Microsoft.Graph(.|.Beta.)PowerShell.Models.\w*> \w*\)[^]*?(WriteObject.*(await response).*;)/gm
+        var writeObjectRegex = /(WriteObject.*(await response).*;)/gm
+        var responseTypeRegexMatch = $.match(responseTypeRegex);
+        if(responseTypeRegexMatch){
+           responseTypeRegexMatch.forEach((item)=>{
+            var writeObjectRegexMatch = writeObjectRegex.exec($);
+            if(writeObjectRegexMatch){
+              var newContent = item.replace(writeObjectRegex, `var result = ${writeObjectRegexMatch[2]}; if(result!=null){WriteObject(result);}`)
+              $ = $.replace(item, newContent);
+            }
+           });
+        }
+        
         return $;
       }