test: add enabled assertion

Author: boschni

src/core/queryObserver.ts

@@ -138,6 +138,13 @@ export class QueryObserver<
 
     this.options = this.client.defaultQueryObserverOptions(options)
 
+    if (
+      typeof this.options.enabled !== 'undefined' &&
+      typeof this.options.enabled !== 'boolean'
+    ) {
+      throw new Error('Expected enabled to be a boolean')
+    }
+
     // Keep previous query key if the user does not supply one
     if (!this.options.queryKey) {
       this.options.queryKey = prevOptions.queryKey