More code cleanup

Author: MaggieKimani1

src/Microsoft.OpenApi.Readers/ParseNodes/MapNode.cs

@@ -132,13 +132,9 @@ public override Dictionary<string, T> CreateSimpleMap<T>(Func<ValueNode, T> map)
                     try
                     {
                         Context.StartObject(key);
-                        JsonValue valueNode = n.Value as JsonValue;
-                        
-                        if (valueNode == null)
-                        {
-                            throw new OpenApiReaderException($"Expected scalar while parsing {typeof(T).Name}", Context);
-                        }
-                        
+                        JsonValue valueNode = n.Value is JsonValue value ? value 
+                        : throw new OpenApiReaderException($"Expected scalar while parsing {typeof(T).Name}", Context);                        
+                       
                         return (key, value: map(new ValueNode(Context, (JsonValue)n.Value)));
                     } finally {
                         Context.EndObject();
@@ -186,11 +182,9 @@ public string GetReferencePointer()
 
         public string GetScalarValue(ValueNode key)
         {
-            var scalarNode = _node[key.GetScalarValue()] as JsonValue;
-            if (scalarNode == null)
-            {
-                throw new OpenApiReaderException($"Expected scalar for key {key.GetScalarValue()}", Context);
-            }
+            var scalarNode = _node[key.GetScalarValue()] is JsonValue jsonValue
+                ? jsonValue
+                : throw new OpenApiReaderException($"Expected scalar while parsing {key.GetScalarValue()}", Context);
 
             return Convert.ToString(scalarNode?.GetValue<object>(), CultureInfo.InvariantCulture);
         }

src/Microsoft.OpenApi.Readers/ParseNodes/OpenApiAnyConverter.cs

@@ -90,7 +90,7 @@ public static JsonNode GetSpecificOpenApiAny(OpenApiAny any, OpenApiSchema schem
             var type = schema?.Type;
             var format = schema?.Format;
 
-            if(value.StartsWith("\""))
+            if(value.StartsWith("\"", StringComparison.OrdinalIgnoreCase))
             {
                 // More narrow type detection for explicit strings, only check types that are passed as strings
                 if (schema == null)

src/Microsoft.OpenApi.Readers/ParseNodes/RootNode.cs

@@ -23,19 +23,14 @@ public RootNode(
 
         public ParseNode Find(JsonPointer referencePointer)
         {
-            var jsonNode = referencePointer.Find(_jsonNode);
-            if (jsonNode == null)
-            {
-                return null;
-            }
+            var jsonNode = referencePointer.Find(_jsonNode) is JsonNode node ? node : null;
 
             return Create(Context, jsonNode);
         }
 
         public MapNode GetMap()
         {
-            var jsonNode = _jsonNode;
-            return new MapNode(Context, jsonNode);
+            return new MapNode(Context, _jsonNode);
         }
     }
 }

src/Microsoft.OpenApi.Readers/ParsingContext.cs

@@ -119,12 +119,12 @@ private static string GetVersion(RootNode rootNode)
 
             if (versionNode != null)
             {
-                return versionNode.GetScalarValue().Replace("\"", "");
+                return versionNode.GetScalarValue().Replace("\"", string.Empty);
             }
 
             versionNode = rootNode.Find(new JsonPointer("/swagger"));
 
-            return versionNode?.GetScalarValue().Replace("\"", "");
+            return versionNode?.GetScalarValue().Replace("\"", string.Empty);
         }
 
         /// <summary>

src/Microsoft.OpenApi.Readers/YamlHelper.cs

@@ -6,7 +6,6 @@
 using System.IO;
 using System.Linq;
 using System.Text.Json.Nodes;
-using System.Xml.Linq;
 using SharpYaml.Serialization;
 using Microsoft.OpenApi.Exceptions;
 
@@ -17,11 +16,7 @@ internal static class YamlHelper
         public static string GetScalarValue(this JsonNode node)
         {
 
-            var scalarNode = node as JsonValue;
-            if (node == null)
-            {
-                throw new OpenApiException($"Expected scalar value.");
-            }
+            var scalarNode = node is JsonValue value ? value : throw new OpenApiException($"Expected scalar value.");
 
             return Convert.ToString(scalarNode?.GetValue<object>(), CultureInfo.InvariantCulture);
         }