feat(pack): support output.entryRootExport

crates/pack-core/src/client/context.rs

@@ -617,6 +617,11 @@ pub async fn get_client_chunking_context(
         builder = builder.chunk_loading_global(chunk_loading_global.clone());
     }
 
+    // Read entry_root_export from config
+    if let Some(entry_root_export) = &*config.entry_root_export().await? {
+        builder = builder.entry_root_export(Some(entry_root_export.clone()));
+    }
+
     if mode.is_development() {
         builder = builder
             .hot_module_replacement()

crates/pack-core/src/config.rs

@@ -360,6 +360,11 @@ pub struct OutputConfig {
     /// This is similar to webpack's `output.chunkLoadingGlobal`.
     /// Default: "TURBOPACK"
     pub chunk_loading_global: Option<RcStr>,
+    /// Expose entry module exports to global scope with the specified name.
+    /// When set, all named exports from the entry module will be available on `window`/`globalThis`
+    /// under the specified name. If set to empty string, will use package.json name.
+    /// Default: None (no exposure)
+    pub entry_root_export: Option<RcStr>,
 }
 
 #[turbo_tasks::value]
@@ -981,6 +986,20 @@ impl Config {
         Ok(Vc::cell(None))
     }
 
+    #[turbo_tasks::function]
+    pub async fn entry_root_export(&self) -> Result<Vc<Option<RcStr>>> {
+        // Check if entry_root_export is configured
+        let entry_root_export = self
+            .output
+            .as_ref()
+            .and_then(|o| o.entry_root_export.as_ref());
+
+        match entry_root_export {
+            Some(name) if !name.is_empty() => Ok(Vc::cell(Some(name.clone()))),
+            _ => Ok(Vc::cell(None)),
+        }
+    }
+
     #[turbo_tasks::function]
     pub fn mode(&self) -> Vc<Mode> {
         self.mode.unwrap_or_default().cell()

crates/pack-schema/src/lib.rs

@@ -316,6 +316,13 @@ pub struct SchemaOutputConfig {
         description = "The global variable name used by the runtime for loading chunks. Default: 'TURBOPACK'"
     )]
     pub chunk_loading_global: Option<String>,
+
+    /// Expose entry module exports to global scope with the specified name
+    #[serde(skip_serializing_if = "Option::is_none")]
+    #[schemars(
+        description = "Expose entry module exports to global scope with the specified name. When set, all named exports from the entry module will be available on window/globalThis under the specified name. If set to empty string, will use package.json name. Default: None (no exposure)"
+    )]
+    pub entry_root_export: Option<String>,
 }
 
 /// Output type

crates/pack-tests/tests/snapshot/runtime/export_entry_exports/config.json

@@ -0,0 +1,15 @@
+{
+    "config": {
+        "entry": [
+            {
+                "import": "input/index.ts",
+                "name": "main"
+            }
+        ],
+        "output": {
+            "path": "output",
+            "entryRootExport": "export-entry-exports"
+        }
+    },
+    "runtimeType": "Production"
+}

crates/pack-tests/tests/snapshot/runtime/export_entry_exports/input/index.ts

@@ -0,0 +1,17 @@
+export function setTernContainer(container: HTMLElement) {
+    console.log('Setting Tern container:', container);
+    return container;
+}
+
+export function initializeApp(config: { theme: string }) {
+    console.log('Initializing app with config:', config);
+    return { success: true, config };
+}
+
+export const APP_VERSION = '1.0.0';
+
+export default {
+    setTernContainer,
+    initializeApp,
+    version: APP_VERSION
+};