Add check for schema property

Fixes angular-schema-form#558 Add check for schema property to prevent
form generation failures when a checkbox is explicitly defined by a
developer (and therefore does not have a schema property) by
@vinceis1337 in angular-schema-form#663

Author: Anthropic

dist/json-schema-form-core.js

@@ -1,6 +1,6 @@
 {
   "name": "json-schema-form-core",
-  "version": "1.0.0-alpha.2",
+  "version": "1.0.0-alpha.3",
   "description": "JSON-Schema and JSON-UI-Schema utilities for form generation.",
   "main": "dist/json-schema-form-core.js",
   "scripts": {

dist/json-schema-form-core.js.map

@@ -111,16 +111,22 @@ export function merge(lookup, form, ignore, options, readonly, asyncTemplates) {
 
     // Special case: checkbox
     // Since have to ternary state we need a default
-    if (obj.type === 'checkbox' && obj.schema['default'] === undefined) {
-      obj.schema['default'] = false;
+    if (obj.type === 'checkbox') {
+      // Check for schema property, as the checkbox may be part of the explicitly defined form
+      if (obj.schema === undefined) {
+        obj.schema = { default: false };
+      }
+      else if (obj.schema['default'] === undefined) {
+        obj.schema['default'] = false;
+      };
     };
 
     // Special case: template type with tempplateUrl that's needs to be loaded before rendering
     // TODO: this is not a clean solution. Maybe something cleaner can be made when $ref support
     // is introduced since we need to go async then anyway
     if (asyncTemplates && obj.type === 'template' && !obj.template && obj.templateUrl) {
       asyncTemplates.push(obj);
-    }
+    };
 
     return obj;
   });