diff --git a/package.json b/package.json
index ae930b8..6750a15 100644
--- a/package.json
+++ b/package.json
@@ -48,7 +48,7 @@
     "@babel/polyfill": "^7.0.0",
     "asyncro": "^3.0.0",
     "autoprefixer": "^9.0.0",
-    "babel-plugin-transform-async-to-promises": "^0.8.1",
+    "babel-plugin-transform-async-to-promises": "^0.8.3",
     "brotli-size": "^0.0.3",
     "camelcase": "^5.0.0",
     "chalk": "^2.4.0",
diff --git a/src/index.js b/src/index.js
index 950aa9d..a9ef3f0 100644
--- a/src/index.js
+++ b/src/index.js
@@ -372,7 +372,7 @@ function createConfig(options, entry, format, writeMeta) {
 							},
 							tsconfigOverride: {
 								compilerOptions: {
-									target: 'es2017',
+									target: 'esnext',
 								},
 							},
 						}),
@@ -384,6 +384,7 @@ function createConfig(options, entry, format, writeMeta) {
 						// supplied configurations we set this option to false. Note
 						// that we never supported using custom babel configs anyway.
 						babelrc: false,
+						extensions: ['.ts', '.tsx', '.js', '.jsx', '.es6', '.es', '.mjs'],
 						exclude: 'node_modules/**',
 						plugins: [
 							require.resolve('@babel/plugin-syntax-jsx'),
diff --git a/test/__snapshots__/index.test.js.snap b/test/__snapshots__/index.test.js.snap
index 91a3818..7abcf94 100644
--- a/test/__snapshots__/index.test.js.snap
+++ b/test/__snapshots__/index.test.js.snap
@@ -1,5 +1,63 @@
 // Jest Snapshot v1, https://goo.gl/fbAQLP
 
+exports[`fixtures async-iife-ts 1`] = `
+"Used script: microbundle
+
+Directory tree:
+
+async-iife-ts
+  dist
+    async-iife-ts.js
+    async-iife-ts.js.map
+    async-iife-ts.mjs
+    async-iife-ts.mjs.map
+    async-iife-ts.umd.js
+    async-iife-ts.umd.js.map
+    index.d.ts
+  package.json
+  src
+    index.ts
+  tsconfig.json
+
+
+Build \\"asyncIifeTs\\" to dist:
+93 B: async-iife-ts.js.gz
+74 B: async-iife-ts.js.br
+93 B: async-iife-ts.mjs.gz
+74 B: async-iife-ts.mjs.br
+164 B: async-iife-ts.umd.js.gz
+123 B: async-iife-ts.umd.js.br"
+`;
+
+exports[`fixtures async-ts 1`] = `
+"Used script: microbundle
+
+Directory tree:
+
+async-ts
+  dist
+    async-ts.js
+    async-ts.js.map
+    async-ts.mjs
+    async-ts.mjs.map
+    async-ts.umd.js
+    async-ts.umd.js.map
+    index.d.ts
+  package.json
+  src
+    index.ts
+  tsconfig.json
+
+
+Build \\"asyncTs\\" to dist:
+158 B: async-ts.js.gz
+122 B: async-ts.js.br
+160 B: async-ts.mjs.gz
+128 B: async-ts.mjs.br
+245 B: async-ts.umd.js.gz
+202 B: async-ts.umd.js.br"
+`;
+
 exports[`fixtures basic 1`] = `
 "Used script: microbundle
 
@@ -310,12 +368,12 @@ esnext-ts
 
 
 Build \\"esnextTs\\" to dist:
-470 B: esnext-ts.js.gz
-404 B: esnext-ts.js.br
-470 B: esnext-ts.mjs.gz
-409 B: esnext-ts.mjs.br
-528 B: esnext-ts.umd.js.gz
-461 B: esnext-ts.umd.js.br"
+841 B: esnext-ts.js.gz
+753 B: esnext-ts.js.br
+842 B: esnext-ts.mjs.gz
+751 B: esnext-ts.mjs.br
+902 B: esnext-ts.umd.js.gz
+804 B: esnext-ts.umd.js.br"
 `;
 
 exports[`fixtures jsx 1`] = `
diff --git a/test/fixtures/async-iife-ts/package.json b/test/fixtures/async-iife-ts/package.json
new file mode 100644
index 0000000..196e228
--- /dev/null
+++ b/test/fixtures/async-iife-ts/package.json
@@ -0,0 +1,3 @@
+{
+	"name": "async-iife-ts"
+}
diff --git a/test/fixtures/async-iife-ts/src/index.ts b/test/fixtures/async-iife-ts/src/index.ts
new file mode 100644
index 0000000..863d5c5
--- /dev/null
+++ b/test/fixtures/async-iife-ts/src/index.ts
@@ -0,0 +1,3 @@
+(async function() {
+	console.log('foo');
+})();
diff --git a/test/fixtures/async-iife-ts/tsconfig.json b/test/fixtures/async-iife-ts/tsconfig.json
new file mode 100644
index 0000000..265086f
--- /dev/null
+++ b/test/fixtures/async-iife-ts/tsconfig.json
@@ -0,0 +1,5 @@
+{
+	"compilerOptions": {
+		"rootDir": "./src"
+	}
+}
diff --git a/test/fixtures/async-ts/package.json b/test/fixtures/async-ts/package.json
new file mode 100644
index 0000000..484645c
--- /dev/null
+++ b/test/fixtures/async-ts/package.json
@@ -0,0 +1,3 @@
+{
+	"name": "async-ts"
+}
diff --git a/test/fixtures/async-ts/src/index.ts b/test/fixtures/async-ts/src/index.ts
new file mode 100644
index 0000000..3098a3a
--- /dev/null
+++ b/test/fixtures/async-ts/src/index.ts
@@ -0,0 +1,3 @@
+export class MyClass {
+	async foo() {}
+}
diff --git a/test/fixtures/async-ts/tsconfig.json b/test/fixtures/async-ts/tsconfig.json
new file mode 100644
index 0000000..265086f
--- /dev/null
+++ b/test/fixtures/async-ts/tsconfig.json
@@ -0,0 +1,5 @@
+{
+	"compilerOptions": {
+		"rootDir": "./src"
+	}
+}
diff --git a/test/fixtures/esnext-ts/src/index.ts b/test/fixtures/esnext-ts/src/index.ts
index 057955a..2816430 100644
--- a/test/fixtures/esnext-ts/src/index.ts
+++ b/test/fixtures/esnext-ts/src/index.ts
@@ -1,10 +1,10 @@
 export default async function foo() {
 	const out = [];
-	for await (const item of [1,2]) {
+	for await (const item of [1, 2]) {
 		out.push(item);
 	}
 
 	return out;
 }
 
-foo().then(console.log)
+foo().then(console.log);