diff --git a/packages/loader/src/shared.ts b/packages/loader/src/shared.ts
index 4d403dd9dc..4b4c4df905 100644
--- a/packages/loader/src/shared.ts
+++ b/packages/loader/src/shared.ts
@@ -218,7 +218,6 @@ export abstract class Loader {
   }
 
   interpolate(source: any) {
-    if (!this.writable) return source
     if (typeof source === 'string') {
       return interpolate(source, this.params, /\$\{\{(.+?)\}\}/g)
     } else if (!source || typeof source !== 'object') {
diff --git a/packages/loader/tests/index.spec.ts b/packages/loader/tests/loader.spec.ts
similarity index 100%
rename from packages/loader/tests/index.spec.ts
rename to packages/loader/tests/loader.spec.ts