Simplifying the output

crates/cli-support/src/js/mod.rs

@@ -1088,6 +1088,28 @@ impl<'a> Context<'a> {
         Ok(())
     }
 
+    fn expose_get_cached_string_from_wasm(&mut self) -> Result<(), Error> {
+        if !self.should_write_global("get_cached_string_from_wasm") {
+            return Ok(());
+        }
+
+        self.expose_get_object();
+        self.expose_get_string_from_wasm()?;
+
+        self.global("
+            function getCachedStringFromWasm(ptr, len) {
+                if (ptr === 0) {
+                    if (len !== 0) {
+                        return getObject(len);
+                    }
+                } else {
+                    return getStringFromWasm(ptr, len);
+                }
+            }
+        ");
+        Ok(())
+    }
+
     fn expose_get_array_js_value_from_wasm(&mut self) -> Result<(), Error> {
         if !self.should_write_global("get_array_js_value_from_wasm") {
             return Ok(());

crates/cli-support/src/js/outgoing.rs

@@ -139,16 +139,10 @@ impl<'a, 'b> Outgoing<'a, 'b> {
                 let len = self.arg(*length);
                 let tmp = self.js.tmp();
 
-                self.js.typescript_required("string");
+                self.js.typescript_optional("string");
-                self.cx.expose_get_object();
+                self.cx.expose_get_cached_string_from_wasm()?;
-                self.cx.expose_get_string_from_wasm()?;
 
-                self.js.prelude(&format!(
+                self.js.prelude(&format!("const v{} = getCachedStringFromWasm({}, {});", tmp, ptr, len));
-                    "const v{tmp} = {ptr} === 0 ? getObject({len}) : getStringFromWasm({ptr}, {len});",
-                    tmp = tmp,
-                    ptr = ptr,
-                    len = len,
-                ));
 
                 if *owned {
                     self.prelude_free_cached_string(&ptr, &len)?;
@@ -332,35 +326,6 @@ impl<'a, 'b> Outgoing<'a, 'b> {
                 self.js.prelude("}");
                 Ok(format!("v{}", i))
             }
-
-            NonstandardOutgoing::OptionCachedString {
-                offset,
-                length,
-                owned,
-            } => {
-                let ptr = self.arg(*offset);
-                let len = self.arg(*length);
-                let tmp = self.js.tmp();
-
-                self.js.typescript_optional("string");
-                self.cx.expose_get_object();
-                self.cx.expose_get_string_from_wasm()?;
-
-                self.js.prelude(&format!("let v{};", tmp));
-
-                self.js.prelude(&format!(
-                    "if ({ptr} === 0) {{ if ({len} !== 0) {{ v{tmp} = getObject({len}); }} }} else {{ v{tmp} = getStringFromWasm({ptr}, {len}); }}",
-                    tmp = tmp,
-                    ptr = ptr,
-                    len = len,
-                ));
-
-                if *owned {
-                    self.prelude_free_cached_string(&ptr, &len)?;
-                }
-
-                Ok(format!("v{}", tmp))
-            }
         }
     }
 

crates/cli-support/src/webidl/outgoing.rs

@@ -88,13 +88,6 @@ pub enum NonstandardOutgoing {
         kind: VectorKind,
     },
 
-    ///
-    OptionCachedString {
-        offset: u32,
-        length: u32,
-        owned: bool,
-    },
-
     /// An optional slice of data is being passed into JS.
     ///
     /// TODO: with some cleverness this could probably use `AllocCopy`.
@@ -462,7 +455,7 @@ impl OutgoingBuilder<'_> {
                 let offset = self.push_wasm(ValType::I32);
                 let length = self.push_wasm(ValType::I32);
                 self.webidl.push(ast::WebidlScalarType::DomString);
-                self.bindings.push(NonstandardOutgoing::OptionCachedString {
+                self.bindings.push(NonstandardOutgoing::CachedString {
                     offset,
                     length,
                     owned: true,
@@ -506,7 +499,7 @@ impl OutgoingBuilder<'_> {
                 let offset = self.push_wasm(ValType::I32);
                 let length = self.push_wasm(ValType::I32);
                 self.webidl.push(ast::WebidlScalarType::DomString);
-                self.bindings.push(NonstandardOutgoing::OptionCachedString {
+                self.bindings.push(NonstandardOutgoing::CachedString {
                     offset,
                     length,
                     owned: false,