items must always be present for type:array

index.js

@@ -35,6 +35,10 @@ function convertSchema(schema, path, parent, parentPath) {
 		schema = convertPatternProperties(schema);
 	}
 
+	if (schema.type === 'array' && typeof schema.items === 'undefined') {
+		schema.items = {};
+	}
+
 	return schema;
 }
 

test/array-items.test.js

@@ -0,0 +1,21 @@
+'use strict';
+
+const convert = require('../');
+const should = require('should');
+
+it('array-items', () => {
+	const schema = {
+		$schema: 'http://json-schema.org/draft-04/schema#',
+		type: 'array',
+	};
+
+	const result = convert(schema);
+
+	const expected = {
+		type: 'array',
+		items: {
+		}
+	};
+
+	should(result).deepEqual(expected, 'converted');
+});