diff --git a/rollup.config.js b/rollup.config.js
index c05d722..99d78bb 100644
--- a/rollup.config.js
+++ b/rollup.config.js
@@ -1,3 +1,4 @@
+import path from 'path';
 import babel from 'rollup-plugin-babel';
 import commonjs from 'rollup-plugin-commonjs';
 import nodeResolve from 'rollup-plugin-node-resolve';
@@ -6,7 +7,7 @@ import pkg from './package.json';
 
 const input = './src/index.js';
 
-const external = id => !id.startsWith('.') && !id.startsWith('/');
+const external = id => !id.startsWith('.') && !path.isAbsolute(id);
 
 export default [
   {