Fix IE11 bundle

rollup/cjs.ie11.js

@@ -1,13 +1,15 @@
 import glob from 'matched';
 import commonjs from '@rollup/plugin-commonjs';
 import typescript from 'rollup-plugin-typescript2';
+import resolve from '@rollup/plugin-node-resolve';
 import mergeConfig from './merge-config';
 
 const dir = './dist/ie11';
 
 const config = {
   input: glob.sync(['src/**/*.ts', '!src/index.ts', '!src/**/*.test.ts']),
   preserveModules: true,
+  external: ['superstruct'],
   output: {
     dir,
     format: 'cjs',
@@ -16,6 +18,11 @@ const config = {
     },
   },
   plugins: [
+    resolve({
+      customResolveOptions: {
+        moduleDirectory: dir,
+      },
+    }),
     commonjs(),
     typescript({
       clean: true,

rollup/merge-config.js

@@ -1,5 +1,4 @@
 import { terser } from 'rollup-plugin-terser';
-import resolve from '@rollup/plugin-node-resolve';
 
 /**
  * Merge rollup config with base config
@@ -8,14 +7,13 @@ import resolve from '@rollup/plugin-node-resolve';
 export default function mergeRollupConfig(config) {
   return {
     ...config,
-    external: ['react-hook-form'],
+    external: ['react-hook-form'].concat(config.external || []),
     output: {
       sourcemap: true,
       exports: 'named',
       ...config.output,
     },
     plugins: [
-      resolve(),
       terser({
         output: { comments: false },
         compress: {

rollup/umd.js

@@ -1,4 +1,5 @@
 import typescript from 'rollup-plugin-typescript2';
+import resolve from '@rollup/plugin-node-resolve';
 import mergeConfig from './merge-config';
 
 const dir = './dist/umd';
@@ -14,6 +15,7 @@ const config = {
     },
   },
   plugins: [
+    resolve(),
     typescript({
       clean: true,
       tsconfigOverride: {