fix: emit CJS build so require('@mcp-ui/client') exposes exports (#211)

The require condition and main field pointed at dist/index.js, a UMD
bundle. Because package.json has "type": "module", Node parses .js as
ESM, so the UMD wrapper's exports check never fires and require()
returns an empty object (reproduces on published 7.1.1).

Add a cjs build output at dist/index.cjs (mirroring @mcp-ui/server) and
point main/exports.require at it. The UMD bundle stays at dist/index.js
for script-tag/CDN consumers.

Co-authored-by: Claude Fable 5 <noreply@anthropic.com>

Author: liady

sdks/typescript/client/package.json

@@ -4,14 +4,14 @@
   "description": "mcp-ui Client SDK",
   "private": false,
   "type": "module",
-  "main": "./dist/index.js",
+  "main": "./dist/index.cjs",
   "module": "./dist/index.mjs",
   "types": "./dist/src/index.d.ts",
   "exports": {
     ".": {
       "types": "./dist/src/index.d.ts",
       "import": "./dist/index.mjs",
-      "require": "./dist/index.js"
+      "require": "./dist/index.cjs"
     }
   },
   "files": [

sdks/typescript/client/vite.config.ts

@@ -17,9 +17,12 @@ export default defineConfig({
     lib: {
       entry: path.resolve(__dirname, 'src/index.ts'),
       name: 'McpUiClient',
-      formats: ['es', 'umd'],
+      // cjs for Node require() compatibility ("type": "module" makes .js files
+      // ESM, so the UMD bundle at index.js is not requirable); umd kept for
+      // script-tag/CDN consumers
+      formats: ['es', 'cjs', 'umd'],
       fileName: (format) =>
-        `index.${format === 'es' ? 'mjs' : format === 'umd' ? 'js' : format + '.js'}`,
+        `index.${format === 'es' ? 'mjs' : format === 'cjs' ? 'cjs' : 'js'}`,
     },
     rollupOptions: {
       external: [