Refactor: Minor safety and modernization updates in processSchema

lib/process-schema.js

@@ -1,36 +1,68 @@
+/**
+ * Keys that contain nested objects with named children (e.g., definitions, properties).
+ * @type {string[]}
+ */
 const NESTED_WITH_NAME = ["definitions", "properties"];
 
+/**
+ * Keys that contain directly nested schema objects (e.g., items, additionalProperties, not).
+ * @type {string[]}
+ */
 const NESTED_DIRECT = ["items", "additionalProperties", "not"];
 
+/**
+ * Keys that contain arrays of schema objects (e.g., oneOf, anyOf, allOf).
+ * @type {string[]}
+ */
 const NESTED_ARRAY = ["oneOf", "anyOf", "allOf"];
 
+/**
+ * Recursively processes a JSON Schema using the visitor pattern.
+ *
+ * @param {{
+ *   schema?: (schema: Record<string, any>, context?: Record<string, any>) => Record<string, any> | void,
+ *   object?: (obj: Record<string, any>, context?: Record<string, any>) => Record<string, any> | void,
+ *   array?: (collection: any[], context?: Record<string, any>) => void
+ * }} visitor - Visitor object with optional handlers for schema, object, and array nodes.
+ * @param {Record<string, any>} json - The JSON Schema node to process.
+ * @param {Record<string, any>} [context] - Optional shared context passed through recursive calls.
+ * @returns {Record<string, any>} - The processed schema node.
+ */
 const processSchema = (visitor, json, context) => {
+	if (!json || typeof json !== "object") return json; // safety check
+
 	json = { ...json };
-	if (visitor.schema) json = visitor.schema(json, context);
+	if (typeof visitor?.schema === "function") {
+		json = visitor.schema(json, context) || json;
+	}
 
 	for (const name of NESTED_WITH_NAME) {
-		if (name in json && json[name] && typeof json[name] === "object") {
-			if (visitor.object) json[name] = visitor.object(json[name], context);
-			for (const key in json[name]) {
+		if (json[name] && typeof json[name] === "object" && !Array.isArray(json[name])) {
+			if (typeof visitor?.object === "function") {
+				json[name] = visitor.object(json[name], context) || json[name];
+			}
+			for (const key of Object.keys(json[name])) {
 				json[name][key] = processSchema(visitor, json[name][key], context);
 			}
 		}
 	}
+
 	for (const name of NESTED_DIRECT) {
-		if (name in json && json[name] && typeof json[name] === "object") {
+		if (json[name] && typeof json[name] === "object" && !Array.isArray(json[name])) {
 			json[name] = processSchema(visitor, json[name], context);
 		}
 	}
+
 	for (const name of NESTED_ARRAY) {
-		if (name in json && Array.isArray(json[name])) {
-			json[name] = json[name].slice();
-			for (let i = 0; i < json[name].length; i++) {
-				json[name][i] = processSchema(visitor, json[name][i], context);
+		if (Array.isArray(json[name])) {
+			json[name] = json[name].map((item) => processSchema(visitor, item, context));
+			if (typeof visitor?.array === "function") {
+				visitor.array(json[name], context);
 			}
-			if (visitor.array) visitor.array(json[name], context);
 		}
 	}
 
 	return json;
 };
+
 module.exports = processSchema;