make all jetstream configurations strict on tests

test_helpers/mod.ts

@@ -41,6 +41,7 @@ export function jsopts() {
     jetstream: {
       max_file_store: 1024 * 1024,
       max_mem_store: 1024 * 1024,
+      strict: true,
       store_dir,
     },
   };
@@ -85,10 +86,64 @@ export function jetstreamExportServerConf(
   return jetstreamServerConf(conf);
 }
 
+
+/**
+ * Checks if the given item is a plain object, excluding arrays and dates.
+ *
+ * @param {*} item - The item to check.
+ * @returns {boolean} True if the item is a plain object, false otherwise.
+ */
+function isObject(item: unknown) {
+  return (item && typeof item === 'object' && !Array.isArray(item) && !(item instanceof Date))
+}
+
+/**
+ * Recursively merges properties from source objects into a target object. If a property at the current level is an object,
+ * and both target and source have it, the property is merged. Otherwise, the source property overwrites the target property.
+ * This function does not modify the source objects and prevents prototype pollution by not allowing __proto__, constructor,
+ * and prototype property names.
+ *
+ * @param {Object} target - The target object to merge properties into.
+ * @param {...Object} sources - One or more source objects from which to merge properties.
+ * @returns {Object} The target object after merging properties from sources.
+ */
+  // deno-lint-ignore no-explicit-any
+  export function deepMerge(target: any, ...sources: any[]) {
+  if (!sources.length) return target
+
+  // Iterate through each source object without modifying the sources array
+  sources.forEach(source => {
+    if (isObject(target) && isObject(source)) {
+      for (const key in source) {
+        if (isObject(source[key])) {
+          if (key === '__proto__' || key === 'constructor' || key === 'prototype') {
+            continue // Skip potentially dangerous keys to prevent prototype pollution.
+          }
+
+          if (!target[key] || !isObject(target[key])) {
+            target[key] = {}
+          }
+
+          deepMerge(target[key], source[key])
+        } else {
+          target[key] = source[key]
+        }
+      }
+    }
+  })
+
+  return target
+}
+
 export function jetstreamServerConf(
   opts: unknown = {},
 ): Record<string, unknown> {
-  const conf = Object.assign(jsopts(), opts);
+  const strict = {
+    jetstream: {
+      strict: true
+    }
+  }
+  const conf = deepMerge(jsopts(), opts, strict);
   if (typeof conf.jetstream.store_dir !== "string") {
     conf.jetstream.store_dir = Deno.makeTempDirSync({ prefix: "jetstream" });
   }