Change behaviour of enable JS to prioritise options passed (#1001)

* Change behaviour of enable JS to prioritize options passed

* Added tests

src/snapshots.js

@@ -208,7 +208,8 @@ export async function* takeStorybookSnapshots(percy, callback, { baseUrl, flags
             // separate story and snapshot options
             let { id, args, globals, queryParams, ...options } = snapshots[0];
 
-            if (flags.dryRun || options.enableJavaScript || percy.config.snapshot.enableJavaScript) {
+            const enableJavaScript = options.enableJavaScript ?? percy.config.snapshot.enableJavaScript;
+            if (flags.dryRun || enableJavaScript) {
               log.debug(`Loading story via previewResource: ${options.name}`);
               // when dry-running or when javascript is enabled, use the preview dom
               options.domSnapshot = previewResource.content;

test/.storybook/snapshot.stories.js

@@ -18,7 +18,8 @@ export const First = () => (
 
 First.parameters = {
   percy: {
-    domTransformation: '(documentElement) => { documentElement.querySelectorAll(".removeMe").forEach(ele => ele.remove()); }'
+    domTransformation: '(documentElement) => { documentElement.querySelectorAll(".removeMe").forEach(ele => ele.remove()); }',
+    enableJavascript: false // this should be priotised over global config
   }
 }
 export const Second = () => (

test/storybook.test.js

@@ -333,6 +333,24 @@ describe('percy storybook', () => {
     expect(callArgs[1][0].domSnapshot).toEqual(previewDOM);
   });
 
+  it('uses the preview dom when javascript is enabled', async () => {
+    fs.writeFileSync('.percy.yml', [
+      'version: 2',
+      'snapshot:',
+      '  enableJavaScript: true'
+    ].join('\n'));
+
+    // eslint-disable-next-line import/no-extraneous-dependencies
+    let { Percy } = await import('@percy/core');
+    spyOn(Percy.prototype, 'snapshot').and.callThrough();
+
+    await storybook(['http://localhost:9000', '--include=First', '--verbose']);
+
+    expect(logger.stderr).toEqual(jasmine.arrayContaining([
+      '[percy:storybook] Loading story: Snapshot: First'
+    ]));
+  });
+
   it('removes element when domTransformation is passed', async () => {
     // eslint-disable-next-line import/no-extraneous-dependencies
     let { Percy } = await import('@percy/core');