Config loader that writes default configs

src/util/config.ts

@@ -1,13 +1,73 @@
-import YAML from "yaml";
-import fs from "fs";
+import { existsSync, readFileSync, writeFileSync } from "fs";
+import { parse, stringify } from "yaml";
+import { z } from "zod";
 
-export function loadConfig<T>(filepath: string, def: T) {
-    try {
-        const data = fs.readFileSync(filepath).toString();
-        const parsed = YAML.parse(data);
-        return parsed as T;
-    } catch (err) {
-        console.error("Unable to load config:", err);
-        return def;
+/**
+ * Load a YAML config file and set default values if config path is nonexistent
+ *
+ * Usage:
+ * ```ts
+ * const config = loadConfig("config/services.yml", {
+ *     enableMPP: false
+ * });
+ * ```
+ * @param configPath Path to load config from
+ * @param defaultConfig Config to use if none is present (will save to path if used)
+ * @returns Parsed YAML config
+ */
+export function loadConfig<T>(configPath: string, defaultConfig: T): T {
+    // Config exists?
+    if (existsSync(configPath)) {
+        // Load config
+        const data = readFileSync(configPath);
+        const config = parse(data.toString());
+
+        const defRecord = defaultConfig as Record<string, any>;
+        let changed = false;
+
+        function mix(
+            obj: Record<string, unknown>,
+            obj2: Record<string, unknown>
+        ) {
+            for (const key of Object.keys(obj2)) {
+                if (typeof obj[key] == "undefined") {
+                    obj[key] = obj2[key];
+                    changed = true;
+                }
+
+                if (typeof obj[key] == "object" && !Array.isArray(obj[key])) {
+                    mix(
+                        obj[key] as Record<string, unknown>,
+                        obj2[key] as Record<string, unknown>
+                    );
                 }
             }
+        }
+
+        // Apply any missing default values
+        mix(config, defRecord);
+
+        // Save config if modified
+        if (changed) writeConfig(configPath, config);
+
+        return config as T;
+    } else {
+        // Write default config to disk and use that
+        writeConfig(configPath, defaultConfig);
+        return defaultConfig as T;
+    }
+}
+
+/**
+ * Write a YAML config to disk
+ * @param configPath
+ * @param config
+ */
+export function writeConfig<T>(configPath: string, config: T) {
+    writeFileSync(
+        configPath,
+        stringify(config, {
+            indent: 4
+        })
+    );
+}