diff --git a/implementations/javascript/package.json b/implementations/javascript/package.json
index 92c31b7..e2a2058 100644
--- a/implementations/javascript/package.json
+++ b/implementations/javascript/package.json
@@ -1,6 +1,6 @@
 {
   "name": "preserves",
-  "version": "0.0.12",
+  "version": "0.0.13",
   "description": "Experimental data serialization format",
   "homepage": "https://gitlab.com/tonyg/preserves",
   "license": "MIT",
diff --git a/implementations/javascript/src/codec.js b/implementations/javascript/src/codec.js
index 4c5b054..73403e3 100644
--- a/implementations/javascript/src/codec.js
+++ b/implementations/javascript/src/codec.js
@@ -3,7 +3,7 @@
 
 if (require('./singletonmodule.js')('leastfixedpoint.com/preserves',
                                     require('../package.json').version,
-                                    'codec.js',
+                                    require('path').basename(module.filename),
                                     module)) return;
 
 const Values = require('./values.js');
diff --git a/implementations/javascript/src/index.js b/implementations/javascript/src/index.js
index e95d2ca..0e66b46 100644
--- a/implementations/javascript/src/index.js
+++ b/implementations/javascript/src/index.js
@@ -2,7 +2,7 @@
 
 if (require('./singletonmodule.js')('leastfixedpoint.com/preserves',
                                     require('../package.json').version,
-                                    'index.js',
+                                    require('path').basename(module.filename),
                                     module)) return;
 
 Object.assign(module.exports, require('./symbols.js'));
diff --git a/implementations/javascript/src/symbols.js b/implementations/javascript/src/symbols.js
index b0b1e3f..e8510da 100644
--- a/implementations/javascript/src/symbols.js
+++ b/implementations/javascript/src/symbols.js
@@ -3,7 +3,7 @@
 
 if (require('./singletonmodule.js')('leastfixedpoint.com/preserves',
                                     require('../package.json').version,
-                                    'symbols.js',
+                                    require('path').basename(module.filename),
                                     module)) return;
 
 const PreserveOn = Symbol.for('PreserveOn');
diff --git a/implementations/javascript/src/values.js b/implementations/javascript/src/values.js
index 809e455..5b28c5b 100644
--- a/implementations/javascript/src/values.js
+++ b/implementations/javascript/src/values.js
@@ -4,7 +4,7 @@
 
 if (require('./singletonmodule.js')('leastfixedpoint.com/preserves',
                                     require('../package.json').version,
-                                    'values.js',
+                                    require('path').basename(module.filename),
                                     module)) return;
 
 const util = require('util');