Extract middleware merge logic into function

Author: bodograumann

modules/openapi-generator/src/main/resources/typescript/configuration.mustache

@@ -113,18 +113,31 @@ export function mergeConfiguration(conf: Configuration, options?: Configuration)
 {{/useInversify}}
 {{^useInversify}}
 export function mergeConfiguration(conf: Configuration, options?: ConfigurationOptions): Configuration {
-    let allMiddleware: Middleware[] = conf.middleware;
-    if (options && options.middleware) {
-        const middlewareMergeStrategy = options.middlewareMergeStrategy || "replace" // default to replace behavior
+    let allMiddleware: Middleware[] = mergeMiddleware(conf.middleware, options?.middleware, options?.middlewareMergeStrategy);
+    if (options) {
+        conf = {
+          baseServer: options.baseServer || conf.baseServer,
+          httpApi: options.httpApi || conf.httpApi,
+          authMethods: options.authMethods || conf.authMethods,
+          middleware: allMiddleware,
+        };
+    }
+    return conf;
+}
+
+function mergeMiddleware(staticMiddleware: Middleware[], calltimeMiddleware?: Middleware[], strategy?: "append" | "prepend" | "replace") {
+    let allMiddleware: Middleware[] = staticMiddleware;
+    if (calltimeMiddleware) {
+        const middlewareMergeStrategy = strategy || "replace" // default to replace behavior
         // call-time middleware provided
-        const calltimeMiddleware: Middleware[] = options.middleware;
+        const calltimeMiddleware: Middleware[] = calltimeMiddleware;
 
         switch(middlewareMergeStrategy) {
         case "append":
-            allMiddleware = conf.middleware.concat(calltimeMiddleware);
+            allMiddleware = staticMiddleware.concat(calltimeMiddleware);
             break;
         case "prepend":
-            allMiddleware = calltimeMiddleware.concat(conf.middleware)
+            allMiddleware = calltimeMiddleware.concat(staticMiddleware)
             break;
         case "replace":
             allMiddleware = calltimeMiddleware
@@ -133,15 +146,7 @@ export function mergeConfiguration(conf: Configuration, options?: ConfigurationO
             throw new Error(`unrecognized middleware merge strategy '${middlewareMergeStrategy}'`);
         }
     }
-    if (options) {
-        conf = {
-          baseServer: options.baseServer || conf.baseServer,
-          httpApi: options.httpApi || conf.httpApi,
-          authMethods: options.authMethods || conf.authMethods,
-          middleware: allMiddleware,
-        };
-    }
-    return conf;
+    return allMiddleware;
 }
 {{/useInversify}}