fix response type restrictions and add tests

Author: stanislav-atr

src/scriptlets/prevent-fetch.js

@@ -42,6 +42,7 @@ import {
  *    - `emptyObj` - empty object
  *    - `emptyArr` - empty array
  * - responseType - optional, string for defining response type, defaults to `default`. Possible values:
+ *    - default
  *    - opaque
  *
  * > Usage with no arguments will log fetch calls to browser console;
@@ -104,9 +105,11 @@ export function preventFetch(source, propsToMatch, responseBody = 'emptyObj', re
         return;
     }
 
-    let allowedResponseType;
-    if (responseType === 'default' || responseType === 'opaque') {
-        allowedResponseType = responseType;
+    // Skip disallowed response types
+    if (!(responseType === 'default' || responseType === 'opaque')) {
+        // eslint-disable-next-line no-console
+        console.log(`Invalid parameter: ${responseType}`);
+        return;
     }
 
     const handlerWrapper = (target, thisArg, args) => {
@@ -139,7 +142,7 @@ export function preventFetch(source, propsToMatch, responseBody = 'emptyObj', re
 
         if (shouldPrevent) {
             hit(source);
-            return noopPromiseResolve(strResponseBody, fetchData.url, allowedResponseType);
+            return noopPromiseResolve(strResponseBody, fetchData.url, responseType);
         }
 
         return Reflect.apply(target, thisArg, args);

tests/scriptlets/prevent-fetch.test.js

@@ -287,4 +287,48 @@ if (!isSupported) {
         assert.strictEqual(window.hit, 'FIRED', 'hit function fired');
         done();
     });
+
+    test('simple fetch - valid response type', async (assert) => {
+        const OPAQUE_RESPONSE_TYPE = 'opaque';
+        const INPUT_JSON_PATH = `${FETCH_OBJECTS_PATH}/test01.json`;
+        const init = {
+            method: 'GET',
+        };
+
+        runScriptlet(name, ['*', '', OPAQUE_RESPONSE_TYPE]);
+        const done = assert.async();
+
+        const response = await fetch(INPUT_JSON_PATH, init);
+
+        assert.strictEqual(response.type, OPAQUE_RESPONSE_TYPE, 'Response type is set');
+        assert.strictEqual(window.hit, 'FIRED', 'hit function fired');
+        done();
+    });
+
+    test('simple fetch - invalid response type', async (assert) => {
+        const INVALID_RESPONSE_TYPE = 'invalid_type';
+        const BASIC_RESPONSE_TYPE = 'basic';
+        const INPUT_JSON_PATH = `${FETCH_OBJECTS_PATH}/test01.json`;
+        const init = {
+            method: 'GET',
+        };
+
+        const expectedJson = {
+            a1: 1,
+            b2: 'test',
+            c3: 3,
+        };
+
+        runScriptlet(name, ['*', '', INVALID_RESPONSE_TYPE]);
+        const done = assert.async();
+
+        const response = await fetch(INPUT_JSON_PATH, init);
+        const actualJson = await response.json();
+
+        assert.deepEqual(actualJson, expectedJson, 'Request is not modified');
+
+        assert.strictEqual(response.type, BASIC_RESPONSE_TYPE, 'Response type is not modified');
+        assert.strictEqual(window.hit, undefined, 'hit function fired');
+        done();
+    });
 }