diff --git a/rollup.config.ts b/rollup.config.ts
index 25cbdc3d6..013ce1274 100644
--- a/rollup.config.ts
+++ b/rollup.config.ts
@@ -30,6 +30,7 @@ export default [{
       include: [ 'src' ],
       exclude: [ 'test', 'benchmark' ],
       compilerOptions: {
+        target: 'es5',
         module: 'ES2015'
       }
     }
@@ -51,6 +52,7 @@ export default [{
         include: [ 'src' ],
         exclude: [ 'test', 'benchmark' ],
         compilerOptions: {
+          target: 'es5',
           module: 'ES2015',
           paths: { 'src/fs': ['src/fs/browser'] }
         }
@@ -73,6 +75,7 @@ export default [{
         include: [ 'src' ],
         exclude: [ 'test', 'benchmark' ],
         compilerOptions: {
+          target: 'es5',
           module: 'ES2015',
           paths: { 'src/fs': ['src/fs/browser'] }
         }
diff --git a/tsconfig.json b/tsconfig.json
index 40fccf9a3..88d8fd5a7 100644
--- a/tsconfig.json
+++ b/tsconfig.json
@@ -1,6 +1,6 @@
 {
   "compilerOptions": {
-    "target": "es5",
+    "target": "es6",
     "module":"CommonJS",
     "lib": ["es2015", "es2016", "es2017", "dom"],
     "sourceMap": true,