feat(index): add AjvClass option (#44)

README.md

@@ -77,6 +77,15 @@ expect.extend(matchersWithOptions({ formats }, (ajv) => {
 }));
 ```
 
+You can also customize the `Ajv` class with the `AjvClass` option:
+
+```js
+import Ajv2020 from 'ajv/dist/2020'
+import { matchersWithOptions } from 'jest-json-schema';
+
+expect.extend(matchersWithOptions({ AjvClass: Ajv2020 }));
+```
+
 ### Verbose errors
 
 Ajv supports a verbose option flag which enables more information about individual

__tests__/index.spec.js

@@ -29,5 +29,15 @@ describe('index', () => {
       matchersWithOptions({}, callback);
       expect(callback).toHaveBeenCalled();
     });
+
+    it('accepts a custom Ajv class', () => {
+      const FakeAjvClass = jest.fn().mockImplementation(() => ({
+        opts: { code: { formats: {} } },
+        addFormat: jest.fn(),
+        addKeyword: jest.fn(),
+      }));
+      matchersWithOptions({ AjvClass: FakeAjvClass });
+      expect(FakeAjvClass).toHaveBeenCalled();
+    });
   });
 });

index.js

@@ -21,10 +21,12 @@ function matchersWithOptions(userOptions = {}, extendAjv) {
   const defaultOptions = {
     allErrors: true,
     strict: false,
+    AjvClass: Ajv,
   };
 
   const options = Object.assign(defaultOptions, userOptions);
-  const ajv = new Ajv(options);
+  const { AjvClass, ...ajvOptions } = options;
+  const ajv = new AjvClass(ajvOptions);
   addFormats(ajv);
   if (typeof extendAjv === 'function') {
     extendAjv(ajv);