Merge pull request #2294 from micalevisk/refactor/issue-2275

perf: cache loaded configuration file
nestjs · Sep 21, 2023 · 197b30f · 197b30f
2 parents b33b2af + 6d1caf2
commit 197b30f
Showing 1 changed file with 38 additions and 17 deletions.
diff --git a/lib/configuration/nest-configuration.loader.ts b/lib/configuration/nest-configuration.loader.ts
@@ -3,10 +3,26 @@ import { Configuration } from './configuration';
 import { ConfigurationLoader } from './configuration.loader';
 import { defaultConfiguration } from './defaults';
 
+/**
+ * A cache table that maps some reader (by its name along with the config path)
+ * to a loaded configuration.
+ * This was added because several commands relies on the app's config in order
+ * to generate some dynanmic content prior running the command itself.
+ */
+const loadedConfigsCache = new Map<string, Required<Configuration>>();
+
 export class NestConfigurationLoader implements ConfigurationLoader {
   constructor(private readonly reader: Reader) {}
 
   public async load(name?: string): Promise<Required<Configuration>> {
+    const cacheEntryKey = `${this.reader.constructor.name}:${name}`;
+    const cachedConfig = loadedConfigsCache.get(cacheEntryKey);
+    if (cachedConfig) {
+       return cachedConfig;
+    }
+
+    let loadedConfig: Required<Configuration> | undefined;
+
     const content: string | undefined = name
       ? await this.reader.read(name)
       : await this.reader.readAnyOf([
@@ -16,23 +32,28 @@ export class NestConfigurationLoader implements ConfigurationLoader {
           'nest.json',
         ]);
 
-    if (!content) {
-      return defaultConfiguration;
-    }
-    const fileConfig = JSON.parse(content);
-    if (fileConfig.compilerOptions) {
-      return {
-        ...defaultConfiguration,
-        ...fileConfig,
-        compilerOptions: {
-          ...defaultConfiguration.compilerOptions,
-          ...fileConfig.compilerOptions,
-        },
-      };
+    if (content) {
+      const fileConfig = JSON.parse(content);
+      if (fileConfig.compilerOptions) {
+        loadedConfig = {
+          ...defaultConfiguration,
+          ...fileConfig,
+          compilerOptions: {
+            ...defaultConfiguration.compilerOptions,
+            ...fileConfig.compilerOptions,
+          },
+        };
+      } else {
+        loadedConfig = {
+          ...defaultConfiguration,
+          ...fileConfig,
+        };
+      }
+    } else {
+      loadedConfig = defaultConfiguration;
     }
-    return {
-      ...defaultConfiguration,
-      ...fileConfig,
-    };
+
+    loadedConfigsCache.set(cacheEntryKey, loadedConfig!);
+    return loadedConfig!;
   }
 }