Fix axios automatically parsing snippet content

This caused JSON values to not be loaded properly

app/assets/javascripts/snippets/components/snippet_blob_edit.vue

@@ -53,7 +53,10 @@ export default {
       const url = joinPaths(baseUrl, this.blob.rawPath);
 
       axios
-        .get(url)
+        .get(url, {
+          // This prevents axios from automatically JSON.parse response
+          transformResponse: [f => f],
+        })
         .then(res => {
           this.notifyAboutUpdates({ content: res.data });
         })

changelogs/unreleased/241199-fix-snippet-loading-json-content.yml

+---
+title: Fix snippets edit not loading JSON values
+merge_request: 40417
+author:
+type: fixed

spec/frontend/snippets/components/snippet_blob_edit_spec.js

@@ -17,6 +17,7 @@ const TEST_PATH = 'foo/bar/test.md';
 const TEST_RAW_PATH = '/gitlab/raw/path/to/blob/7';
 const TEST_FULL_PATH = joinPaths(TEST_HOST, TEST_RAW_PATH);
 const TEST_CONTENT = 'Lorem ipsum dolar sit amet,\nconsectetur adipiscing elit.';
+const TEST_JSON_CONTENT = '{"abc":"lorem ipsum"}';
 
 const TEST_BLOB = {
   id: TEST_ID,
@@ -66,7 +67,7 @@ describe('Snippet Blob Edit component', () => {
   });
 
   describe('with not loaded blob', () => {
-    beforeEach(async () => {
+    beforeEach(() => {
       createComponent();
     });
 
@@ -100,6 +101,20 @@ describe('Snippet Blob Edit component', () => {
     });
   });
 
+  describe('with unloaded blob and JSON content', () => {
+    beforeEach(() => {
+      axiosMock.onGet(TEST_FULL_PATH).reply(200, TEST_JSON_CONTENT);
+      createComponent();
+    });
+
+    // This checks against this issue https://gitlab.com/gitlab-org/gitlab/-/issues/241199
+    it('emits raw content', async () => {
+      await waitForPromises();
+
+      expect(getLastUpdatedArgs()).toEqual({ content: TEST_JSON_CONTENT });
+    });
+  });
+
   describe('with error', () => {
     beforeEach(() => {
       axiosMock.reset();