diff --git a/ext/wasm/api/sqlite3-wasm.c b/ext/wasm/api/sqlite3-wasm.c
index 6cda681a70..8e382e7f53 100644
--- a/ext/wasm/api/sqlite3-wasm.c
+++ b/ext/wasm/api/sqlite3-wasm.c
@@ -503,7 +503,7 @@ static void kvstorageMakeKey(
 ** An internal level of indirection for accessing the static
 ** kvstorageMakeKey() from EM_JS()-generated functions. This must be
 ** made available for export via Emscripten but is not intended to be
-** used from client code. If called with a NULL zClass it is a no-op.
+** used from client code. If called with a NULL zKeyOut it is a no-op.
 ** It returns KVSTORAGE_KEY_SZ, so JS code (which cannot see that
 ** constant) may call it with NULL arguments to get the size of the
 ** allocation they'll need for a kvvfs key.
@@ -514,7 +514,7 @@ static void kvstorageMakeKey(
 int sqlite3_wasm__kvvfsMakeKey(const char *zClass,
                                   const char *zKeyIn,
                                   char *zKeyOut){
-  if(zClass) kvstorageMakeKey(zClass, zKeyIn, zKeyOut);
+  if(zKeyOut) kvstorageMakeKey(zClass, zKeyIn, zKeyOut);
   return KVSTORAGE_KEY_SZ;
 }
 
@@ -559,14 +559,33 @@ EM_JS(void, kvstorageMakeKeyJS,
 });
 #endif
 
+/*
+** Internal helper for kvstorageWrite/Read/Delete() which creates a
+** storage key for the given zClass/zKeyIn combination. Returns a
+** pointer to the key: a C string allocated on the WASM stack, or 0 if
+** allocation fails. It is up to the caller to save/restore the stack
+** before/after this operation.
+*/
+EM_JS(const char *, kvstorageMakeKeyOnJSStack,
+      (const char *zClass, const char *zKeyIn),{
+  if( 0==zClass || 0==zKeyIn) return 0;
+  const zXKey = stackAlloc(_sqlite3_wasm__kvvfsMakeKey(0,0,0));
+  if(zXKey) _sqlite3_wasm__kvvfsMakeKey(zClass, zKeyIn, zXKey);
+  return zXKey;
+});
+
+/*
+** JS impl of kvstorageWrite(). Main docs are in the C impl. This impl
+** writes zData to the global sessionStorage (if zClass starts with
+** 's') or localStorage, using a storage key derived from zClass and
+** zKey.
+*/
 EM_JS(int, kvstorageWrite,
       (const char *zClass, const char *zKey, const char *zData),{
   const stack = stackSave();
   try {
-    //const zXKey = stackAlloc(kvstorageMakeKeyJS());
-    //kvstorageMakeKeyJS(zClass, zKey, zXKey);
-    const zXKey = stackAlloc(_sqlite3_wasm__kvvfsMakeKey(0,0,0));
-    _sqlite3_wasm__kvvfsMakeKey(zClass, zKey, zXKey);
+    const zXKey = kvstorageMakeKeyOnJSStack(zClass,zKey);
+    if(!zXKey) return 1/*OOM*/;
     const jKey = UTF8ToString(zXKey);
     /**
        We could simplify this function and eliminate the
@@ -586,11 +605,18 @@ EM_JS(int, kvstorageWrite,
   return 0;
 });
 
+/*
+** JS impl of kvstorageDelete(). Main docs are in the C impl. This
+** impl generates a key derived from zClass and zKey, and removes the
+** matching entry (if any) from global sessionStorage (if zClass
+** starts with 's') or localStorage.
+*/
 EM_JS(int, kvstorageDelete,
       (const char *zClass, const char *zKey),{
   const stack = stackSave();
   try {
-    const zXKey = stackAlloc(_sqlite3_wasm__kvvfsMakeKey(0,0,0));
+    const zXKey = kvstorageMakeKeyOnJSStack(zClass,zKey);
+    if(!zXKey) return 1/*OOM*/;
     _sqlite3_wasm__kvvfsMakeKey(zClass, zKey, zXKey);
     const jKey = UTF8ToString(zXKey);
     ((115/*=='s'*/===getValue(zClass))
@@ -604,16 +630,21 @@ EM_JS(int, kvstorageDelete,
   return 0;
 });
 
+/*
+** JS impl of kvstorageRead(). Main docs are in the C impl. This impl
+** reads its data from the global sessionStorage (if zClass starts
+** with 's') or localStorage, using a storage key derived from zClass
+** and zKey.
+*/
 EM_JS(int, kvstorageRead,
       (const char *zClass, const char *zKey, char *zBuf, int nBuf),{
   const stack = stackSave();
   try {
-    const zXKey = stackAlloc(_sqlite3_wasm__kvvfsMakeKey(0,0,0));
-    _sqlite3_wasm__kvvfsMakeKey(zClass, zKey, zXKey);
+    const zXKey = kvstorageMakeKeyOnJSStack(zClass,zKey);
+    if(!zXKey) return 1/*OOM*/;
     const jKey = UTF8ToString(zXKey);
-    const storage = (115/*=='s'*/===getValue(zClass))
-      ? sessionStorage : localStorage;
-    const jV = storage.getItem(jKey);
+    const jV = ((115/*=='s'*/===getValue(zClass))
+                ? sessionStorage : localStorage).getItem(jKey);
     if(!jV) return -1;
     const nV = jV.length /* Note that we are relying 100% on v being
                             ASCII so that jV.length is equal to the
@@ -661,7 +692,7 @@ int sqlite3_wasm__emjs_test(int whichOp){
       kvstorageDelete(zClass, zKey);
       break;
   default:
-    //kvstorageMakeKeyJS(0,0,0) /* force Emscripten to include this */;
+    kvstorageMakeKeyOnJSStack(0,0) /* force Emscripten to include this */;
     break;
   }
   return rc;
diff --git a/manifest b/manifest
index 64d9baf481..fc069fb45b 100644
--- a/manifest
+++ b/manifest
@@ -1,5 +1,5 @@
-C Add\sEM_JS()\simpl\sfor\skvstorageRead().
-D 2022-09-11T04:49:29.771
+C Minor\scleanups\sand\sdocs\sfor\sthe\sEM_JS()\simpls\sof\sthe\skvvfs\sread/write/delete\sops.
+D 2022-09-11T05:38:39.331
 F .fossil-settings/empty-dirs dbb81e8fc0401ac46a1491ab34a7f2c7c0452f2f06b54ebb845d024ca8283ef1
 F .fossil-settings/ignore-glob 35175cdfcf539b2318cb04a9901442804be81cd677d8b889fcc9149c21f239ea
 F LICENSE.md df5091916dbb40e6e9686186587125e1b2ff51f022cc334e886c19a0e9982724
@@ -488,7 +488,7 @@ F ext/wasm/api/sqlite3-api-opfs.js 011799db398157cbd254264b6ebae00d7234b93d0e9e8
 F ext/wasm/api/sqlite3-api-prologue.js 88e58145b0c71b00cd523b656016193d6ce8cf22c7ece8225838625f9187e6d1
 F ext/wasm/api/sqlite3-api-worker1.js 73579555563b789785ae83724014eaf31811073aad9be6596c8336ffb51edd71
 F ext/wasm/api/sqlite3-wasi.h 25356084cfe0d40458a902afb465df8c21fc4152c1d0a59b563a3fba59a068f9
-F ext/wasm/api/sqlite3-wasm.c af771ebd94f4c75bb99823d84667a47ecee1425a05b73f13a7c7ff2b368e439d
+F ext/wasm/api/sqlite3-wasm.c ca61244ff11992d82f0abe30563f6a46b5bc5ba6ae6e3fe0de813a539d032638
 F ext/wasm/batch-runner.html 23209ade7981acce7ecd79d6eff9f4c5a4e8b14ae867ac27cd89b230be640fa6
 F ext/wasm/batch-runner.js a727cbbffe63fd17fb5a590dc679f0b13bd51880e8f84b461d7df246417689e8
 F ext/wasm/common/SqliteTestUtil.js 529161a624265ba84271a52db58da022649832fa1c71309fb1e02cc037327a2b
@@ -2019,8 +2019,8 @@ F vsixtest/vsixtest.tcl 6a9a6ab600c25a91a7acc6293828957a386a8a93
 F vsixtest/vsixtest.vcxproj.data 2ed517e100c66dc455b492e1a33350c1b20fbcdc
 F vsixtest/vsixtest.vcxproj.filters 37e51ffedcdb064aad6ff33b6148725226cd608e
 F vsixtest/vsixtest_TemporaryKey.pfx e5b1b036facdb453873e7084e1cae9102ccc67a0
-P a4bd96f5348e607d0fcb627b751f9d86a188173a4b3bfb2c95f92913a78bd31e
-R 310c3e2e3269e2d647346b038874eb9d
+P 06610314fcf644f323c2f7ae11d7f4349b195e66d0ebbee590438dd99d97eb96
+R 57acbb8d05cac7106145ba92b2f60bd7
 U stephan
-Z 24c87f794d1a08fdf28cff48f949d74b
+Z a67cf75775135685688642fe9cc532b8
 # Remove this line to create a well-formed Fossil manifest.
diff --git a/manifest.uuid b/manifest.uuid
index e21a71990d..f196ec7f1b 100644
--- a/manifest.uuid
+++ b/manifest.uuid
@@ -1 +1 @@
-06610314fcf644f323c2f7ae11d7f4349b195e66d0ebbee590438dd99d97eb96
\ No newline at end of file
+53b7572e441be4b4b29b4228d0f95b24457d7faaf6c0b568ed5c970a55e21ffb
\ No newline at end of file