3 files changed, 15 insertions, 7 deletions
diff --git a/cli/js/compiler_api_test.ts b/cli/js/compiler_api_test.ts
index a6baecbf5..82f72cdef 100644
--- a/cli/js/compiler_api_test.ts
+++ b/cli/js/compiler_api_test.ts
@@ -94,14 +94,14 @@ test(async function bundleApiSources() {
     "/bar.ts": `export const bar = "bar";\n`
   });
   assert(diagnostics == null);
-  assert(actual.includes(`__inst("foo")`));
+  assert(actual.includes(`__inst_s("foo")`));
   assert(actual.includes(`__exp["bar"]`));
 });
 
 test(async function bundleApiNoSources() {
   const [diagnostics, actual] = await bundle("./cli/tests/subdir/mod1.ts");
   assert(diagnostics == null);
-  assert(actual.includes(`__inst("mod1")`));
+  assert(actual.includes(`__inst_s("mod1")`));
   assert(actual.includes(`__exp["printHello3"]`));
 });
 
diff --git a/cli/js/compiler_bundler.ts b/cli/js/compiler_bundler.ts
index b9893620a..f8f0b48e8 100644
--- a/cli/js/compiler_bundler.ts
+++ b/cli/js/compiler_bundler.ts
@@ -42,9 +42,16 @@ export function buildBundle(
   rootName = normalizeUrl(rootName)
     .replace(sharedPath, "")
     .replace(/\.\w+$/i, "");
+  // If one of the modules requires support for top-level-await, TypeScript will
+  // emit the execute function as an async function.  When this is the case we
+  // need to bubble up the TLA to the instantiation, otherwise we instantiate
+  // synchronously.
+  const hasTla = data.match(/execute:\sasync\sfunction\s/);
   let instantiate: string;
   if (rootExports && rootExports.length) {
-    instantiate = `const __exp = await __inst("${rootName}");\n`;
+    instantiate = hasTla
+      ? `const __exp = await __inst("${rootName}");\n`
+      : `const __exp = __inst_s("${rootName}");\n`;
     for (const rootExport of rootExports) {
       if (rootExport === "default") {
         instantiate += `export default __exp["${rootExport}"];\n`;
@@ -53,7 +60,9 @@ export function buildBundle(
       }
     }
   } else {
-    instantiate = `await __inst("${rootName}");\n`;
+    instantiate = hasTla
+      ? `await __inst("${rootName}");\n`
+      : `__inst_s("${rootName}");\n`;
   }
   return `${SYSTEM_LOADER}\n${data}\n${instantiate}`;
 }
diff --git a/cli/tests/bundle.test.out b/cli/tests/bundle.test.out
index 1379eb7e5..778754c34 100644
--- a/cli/tests/bundle.test.out
+++ b/cli/tests/bundle.test.out
@@ -1,6 +1,5 @@
 [WILDCARD]
-let System;
-let __inst;
+let System, __inst, __inst_s;
 [WILDCARD]
 (() => {
 [WILDCARD]
@@ -16,7 +15,7 @@ System.register("mod1", ["subdir2/mod2"], function (exports_3, context_3) {
 [WILDCARD]
 });
 
-const __exp = await __inst("mod1");
+const __exp = __inst_s("mod1");
 export const returnsHi = __exp["returnsHi"];
 export const returnsFoo2 = __exp["returnsFoo2"];
 export const printHello3 = __exp["printHello3"];