diff --git a/types/uglify-js/index.d.ts b/types/uglify-js/index.d.ts
index cab53cb4db..eca756bd53 100644
--- a/types/uglify-js/index.d.ts
+++ b/types/uglify-js/index.d.ts
@@ -10,7 +10,7 @@ export interface ParseOptions {
     bare_returns?: boolean;
     html5_comments?: boolean;
     /** Support `#!command` as the first line */
-    shebang: boolean;
+    shebang?: boolean;
 }
 
 export interface CompressOptions {
@@ -198,6 +198,7 @@ export interface MinifyOptions {
 
 export interface MinifyOutput {
     error?: Error;
+    warnings?: string[];
     code: string;
     map: string;
 }
diff --git a/types/uglify-js/uglify-js-tests.ts b/types/uglify-js/uglify-js-tests.ts
index 6b146ab0e7..19c11dfdf1 100644
--- a/types/uglify-js/uglify-js-tests.ts
+++ b/types/uglify-js/uglify-js-tests.ts
@@ -20,7 +20,7 @@ minify(code, {
     }
 });
 
-minify(code, {
+const output = minify(code, {
     warnings: 'verbose',
     mangle: {
         properties: {
@@ -34,3 +34,7 @@ minify(code, {
         arguments: true
     }
 });
+
+if (output.warnings) {
+    output.warnings.filter(x => x === 'Dropping unused variable');
+}