diff --git a/.gitignore b/.gitignore
index c6bba59..ee50711 100644
--- a/.gitignore
+++ b/.gitignore
@@ -128,3 +128,6 @@ dist
 .yarn/build-state.yml
 .yarn/install-state.gz
 .pnp.*
+
+# example.js spec folder
+/spec
diff --git a/builder.cjs b/builder.cjs
index 91911a5..22234c4 100644
--- a/builder.cjs
+++ b/builder.cjs
@@ -22,7 +22,7 @@ class HyperdispatchNamespace {
 
 module.exports = class Hyperdispatch {
   constructor (schema, dispatchJson, { offset, dispatchDir = null, schemaDir = null } = {}) {
-    if (dispatchJson && dispatchJson.offset !== offset) {
+    if (dispatchJson && offset && dispatchJson.offset !== offset) {
       throw new Error('Cannot change the hyperdispatch offset once it has been defined once')
     }
     this.schema = schema
diff --git a/package.json b/package.json
index afe99d6..874e0a0 100644
--- a/package.json
+++ b/package.json
@@ -22,7 +22,8 @@
     }
   },
   "scripts": {
-    "test": "standard && brittle test/index.js"
+    "test": "standard && brittle test/index.js && npm run example:rebuild",
+    "example:rebuild": "node example.js && node example.js"
   },
   "repository": {
     "type": "git",