From dbe5977809bfbb0f645f758e5a0985cd024e30c7 Mon Sep 17 00:00:00 2001
From: Guy Bedford <gbedford@cloudflare.com>
Date: Tue, 10 Mar 2026 22:12:44 -0400
Subject: [PATCH 1/3] wasm: support js string constant esm import

Extends the Wasm ESM Integration for importing WebAssembly
modules in either the source phase or instance phase to support
importing static JS string constants from the special
import name `wasm:js/string-constants`.
---
 doc/api/esm.md                                  |   9 +++++++++
 lib/internal/modules/esm/translators.js         |   1 +
 .../fixtures/es-modules/js-string-builtins.wasm | Bin 325 -> 401 bytes
 test/fixtures/es-modules/js-string-builtins.wat |   8 ++++++++
 .../es-modules/test-wasm-js-string-builtins.mjs |   1 +
 5 files changed, 19 insertions(+)

diff --git a/doc/api/esm.md b/doc/api/esm.md
index 5396acfd53d65c..f6ac6f457b8947 100644
--- a/doc/api/esm.md
+++ b/doc/api/esm.md
@@ -809,6 +809,15 @@ imports and they cannot be inspected via `WebAssembly.Module.imports(mod)`
 or virtualized unless recompiling the module using the direct
 `WebAssembly.compile` API with string builtins disabled.
 
+String constants may also be imported from the `wasm:js/string-constants` builtin
+import URL, allowing static JS string globals to be defined:
+
+```text
+(module
+  (import "wasm:js/string-constants" "hello" (global $hello externref))
+)
+```
+
 Importing a module in the source phase before it has been instantiated will also
 use the compile-time builtins automatically:
 
diff --git a/lib/internal/modules/esm/translators.js b/lib/internal/modules/esm/translators.js
index 2af52e4b9435ea..968e25ebad9521 100644
--- a/lib/internal/modules/esm/translators.js
+++ b/lib/internal/modules/esm/translators.js
@@ -522,6 +522,7 @@ translators.set('wasm', function(url, translateContext) {
   try {
     compiled = new WebAssembly.Module(source, {
       builtins: ['js-string'],
+      importedStringConstants: "wasm:js/string-constants"
     });
   } catch (err) {
     err.message = errPath(url) + ': ' + err.message;
diff --git a/test/fixtures/es-modules/js-string-builtins.wasm b/test/fixtures/es-modules/js-string-builtins.wasm
index b4c08587dd08e715fa2a79fead8fc46143d949d2..fe520bab1fbbf5af043b905c4729d2e2ce2746fa 100644
GIT binary patch
delta 157
zcmX@gG?7__A+b1@k%57MQJf`#F`uzMfhj+qF(n^N)h948<}+opOjPjDkthc$w8|>h
zFD@y{%uClz&d)0@Nz5xLX3a>=$;oHVXJBS!VPIrpX18RSSg6a#k)B%O0g_>0<C15Y
vxKL7ng+ZBtn_(^^OI~7bDq|Y^#G_H%Y@9%4@n91s%QLERv2!poKnw%`gz_kJ

delta 100
zcmbQpe3VInA+b1@k%57MQJ6V_F`uzMfhj+qF(n^N)iZfAPgL>XWM*MzU}R#~W1cue
tSDj0WnT<h#L4bjq14t<_3NXSLOxz3|j4XMHxv7lNY!m-PO-^J~0|1j|5!3(x

diff --git a/test/fixtures/es-modules/js-string-builtins.wat b/test/fixtures/es-modules/js-string-builtins.wat
index 9bc55a8fa750cc..08f4ade8c4151c 100644
--- a/test/fixtures/es-modules/js-string-builtins.wat
+++ b/test/fixtures/es-modules/js-string-builtins.wat
@@ -4,11 +4,15 @@
   (import "wasm:js-string" "length" (func $string_length (param externref) (result i32)))
   (import "wasm:js-string" "concat" (func $string_concat (param externref externref) (result (ref extern))))
   (import "wasm:js-string" "equals" (func $string_equals (param externref externref) (result i32)))
+
+  ;; Import a string constant via importedStringConstants
+  (import "wasm:js/string-constants" "hello" (global $hello externref))
   
   ;; Export functions that use the builtins
   (export "getLength" (func $get_length))
   (export "concatStrings" (func $concat_strings))
   (export "compareStrings" (func $compare_strings))
+  (export "getHello" (func $get_hello))
   
   (func $get_length (param $str externref) (result i32)
     local.get $str
@@ -26,4 +30,8 @@
     local.get $str2
     call $string_equals
   )
+
+  (func $get_hello (result externref)
+    global.get $hello
+  )
 )
\ No newline at end of file
diff --git a/test/fixtures/es-modules/test-wasm-js-string-builtins.mjs b/test/fixtures/es-modules/test-wasm-js-string-builtins.mjs
index 2364f246b2558d..c76dcc39894932 100644
--- a/test/fixtures/es-modules/test-wasm-js-string-builtins.mjs
+++ b/test/fixtures/es-modules/test-wasm-js-string-builtins.mjs
@@ -6,3 +6,4 @@ strictEqual(wasmExports.getLength('hello'), 5);
 strictEqual(wasmExports.concatStrings('hello', ' world'), 'hello world');
 strictEqual(wasmExports.compareStrings('test', 'test'), 1);
 strictEqual(wasmExports.compareStrings('test', 'different'), 0);
+strictEqual(wasmExports.getHello(), 'hello');

From 5bde15ddf42c62a124e649adf5c2029037e0db0b Mon Sep 17 00:00:00 2001
From: Guy Bedford <gbedford@cloudflare.com>
Date: Wed, 11 Mar 2026 10:09:33 -0400
Subject: [PATCH 2/3] lint fix

---
 lib/internal/modules/esm/translators.js | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/internal/modules/esm/translators.js b/lib/internal/modules/esm/translators.js
index 968e25ebad9521..7a665dfb1cf72f 100644
--- a/lib/internal/modules/esm/translators.js
+++ b/lib/internal/modules/esm/translators.js
@@ -522,7 +522,7 @@ translators.set('wasm', function(url, translateContext) {
   try {
     compiled = new WebAssembly.Module(source, {
       builtins: ['js-string'],
-      importedStringConstants: "wasm:js/string-constants"
+      importedStringConstants: "wasm:js/string-constants",
     });
   } catch (err) {
     err.message = errPath(url) + ': ' + err.message;

From 98a6cb3f9fdbe39293331f3635f4f8e67b48882b Mon Sep 17 00:00:00 2001
From: Guy Bedford <guybedford@gmail.com>
Date: Wed, 11 Mar 2026 10:28:50 -0400
Subject: [PATCH 3/3] Update lib/internal/modules/esm/translators.js

Co-authored-by: James Sumners <jsumners@newrelic.com>
---
 lib/internal/modules/esm/translators.js | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/internal/modules/esm/translators.js b/lib/internal/modules/esm/translators.js
index 7a665dfb1cf72f..c3de26ccc5c4ab 100644
--- a/lib/internal/modules/esm/translators.js
+++ b/lib/internal/modules/esm/translators.js
@@ -522,7 +522,7 @@ translators.set('wasm', function(url, translateContext) {
   try {
     compiled = new WebAssembly.Module(source, {
       builtins: ['js-string'],
-      importedStringConstants: "wasm:js/string-constants",
+      importedStringConstants: 'wasm:js/string-constants',
     });
   } catch (err) {
     err.message = errPath(url) + ': ' + err.message;