fix(rollup): use cjs compatible json exports

nuxt/framework#1335

src/builder/rollup.ts

@@ -6,11 +6,11 @@ import { nodeResolve } from '@rollup/plugin-node-resolve'
 import alias from '@rollup/plugin-alias'
 import esbuild from 'rollup-plugin-esbuild'
 import dts from 'rollup-plugin-dts'
-import json from '@rollup/plugin-json'
 import { relative, resolve } from 'pathe'
 import consola from 'consola'
 import { getpkg } from '../utils'
 import type { BuildContext } from '../types'
+import { JSONPlugin } from './utils/json'
 import { CJSBridgePlugin } from './utils/cjs-bridge'
 
 export async function rollupBuild (ctx: BuildContext) {
@@ -128,7 +128,7 @@ export function getRollupOptions (ctx: BuildContext): RollupOptions {
         preferBuiltins: true
       }),
 
-      json({
+      JSONPlugin({
         preferConst: true
       }),
 

src/builder/utils/json.ts

@@ -0,0 +1,19 @@
+import type { Plugin } from 'rollup'
+import type { RollupJsonOptions } from '@rollup/plugin-json'
+import rollupJSONPlugin from '@rollup/plugin-json'
+
+const EXPORT_DEFAULT = 'export default '
+
+export function JSONPlugin (options: RollupJsonOptions): Plugin {
+  const plugin = rollupJSONPlugin(options)
+  return <Plugin>{
+    ...plugin,
+    transform (code, id) {
+      const res = plugin.transform!.call(this, code, id)
+      if (res && typeof res !== 'string' && 'code' in res && res.code && res.code.startsWith(EXPORT_DEFAULT)) {
+        res.code = res.code.replace(EXPORT_DEFAULT, 'module.exports = ')
+      }
+      return res
+    }
+  }
+}