diff --git a/crates/test-support/src/lib.rs b/crates/test-support/src/lib.rs
index be3831a4..1e7b82b6 100644
--- a/crates/test-support/src/lib.rs
+++ b/crates/test-support/src/lib.rs
@@ -168,6 +168,7 @@ impl Project {
             .arg("--noUnusedLocals")
             .arg("--noUnusedParameters")
             .arg("--noImplicitReturns")
+            .arg("--declaration")
             .arg("--lib")
             .arg("es6");
         run(&mut cmd, "node");
diff --git a/crates/wasm-bindgen-cli-support/src/ts.rs b/crates/wasm-bindgen-cli-support/src/ts.rs
index 6a296b35..a55baef2 100644
--- a/crates/wasm-bindgen-cli-support/src/ts.rs
+++ b/crates/wasm-bindgen-cli-support/src/ts.rs
@@ -370,7 +370,7 @@ impl Js {
             }
 
             if extra_exports_interface.len() == 0 {
-                extra_exports_interface.push_str("interface ExtraExports {\n");
+                extra_exports_interface.push_str("export interface ExtraExports {\n");
                 exports_interface.push_str("extra: ExtraExports;\n");
                 exports.push_str("extra: {\n");
             }
@@ -417,7 +417,7 @@ impl Js {
             }
 
             if extra_imports_interface.len() == 0 {
-                extra_imports_interface.push_str("interface ExtraImports {\n");
+                extra_imports_interface.push_str("export interface ExtraImports {\n");
                 imports_interface.push_str("env: ExtraImports;\n");
             }
             imports_object.push_str(import);