Extract ReplyPlaceholder from NoteableDiscussion component

app/assets/javascripts/notes/components/discussion_reply_placeholder.vue

+<script>
+export default {
+  name: 'ReplyPlaceholder',
+};
+</script>
+
+<template>
+  <button
+    ref="button"
+    type="button"
+    class="js-vue-discussion-reply btn btn-text-field"
+    :title="s__('MergeRequests|Add a reply')"
+    @click="$emit('onClick')"
+  >
+    {{ s__('MergeRequests|Reply...') }}
+  </button>
+</template>

app/assets/javascripts/notes/components/noteable_discussion.vue

@@ -24,6 +24,7 @@ import autosave from '../mixins/autosave';
 import noteable from '../mixins/noteable';
 import resolvable from '../mixins/resolvable';
 import discussionNavigation from '../mixins/discussion_navigation';
+import ReplyPlaceholder from './discussion_reply_placeholder.vue';
 import jumpToNextDiscussionButton from './discussion_jump_to_next_button.vue';
 
 export default {
@@ -39,6 +40,7 @@ export default {
     resolveDiscussionButton,
     jumpToNextDiscussionButton,
     toggleRepliesWidget,
+    ReplyPlaceholder,
     placeholderNote,
     placeholderSystemNote,
     systemNote,
@@ -447,14 +449,7 @@ Please check your network connection and try again.`;
               >
                 <template v-if="!isReplying && canReply">
                   <div class="discussion-with-resolve-btn">
-                    <button
-                      type="button"
-                      class="js-vue-discussion-reply btn btn-text-field qa-discussion-reply"
-                      title="Add a reply"
-                      @click="showReplyForm"
-                    >
-                      Reply...
-                    </button>
+                    <reply-placeholder class="qa-discussion-reply" @onClick="showReplyForm" />
                     <resolve-discussion-button
                       v-if="discussion.resolvable"
                       :is-resolving="isResolving"

changelogs/unreleased/refactor-56370-extract-reply-placeholder-component.yml

+---
+title: Extracted ReplyPlaceholder to its own component
+merge_request: 24507
+author: Martin Hobert
+type: other

locale/gitlab.pot

@@ -4393,9 +4393,15 @@ msgstr ""
 msgid "Merge requests are a place to propose changes you've made to a project and discuss those changes with others"
 msgstr ""
 
+msgid "MergeRequests|Add a reply"
+msgstr ""
+
 msgid "MergeRequests|Jump to next unresolved discussion"
 msgstr ""
 
+msgid "MergeRequests|Reply..."
+msgstr ""
+
 msgid "MergeRequests|Resolve this discussion in a new issue"
 msgstr ""
 

spec/javascripts/notes/components/discussion_reply_placeholder_spec.js

+import ReplyPlaceholder from '~/notes/components/discussion_reply_placeholder.vue';
+import { shallowMount, createLocalVue } from '@vue/test-utils';
+
+const localVue = createLocalVue();
+
+describe('ReplyPlaceholder', () => {
+  let wrapper;
+
+  beforeEach(() => {
+    wrapper = shallowMount(ReplyPlaceholder, {
+      localVue,
+    });
+  });
+
+  afterEach(() => {
+    wrapper.destroy();
+  });
+
+  it('emits onClick even on button click', () => {
+    const button = wrapper.find({ ref: 'button' });
+
+    button.trigger('click');
+
+    expect(wrapper.emitted()).toEqual({
+      onClick: [[]],
+    });
+  });
+
+  it('should render reply button', () => {
+    const button = wrapper.find({ ref: 'button' });
+
+    expect(button.text()).toEqual('Reply...');
+  });
+});

spec/javascripts/notes/components/noteable_discussion_spec.js

 import { shallowMount, createLocalVue } from '@vue/test-utils';
 import createStore from '~/notes/stores';
 import noteableDiscussion from '~/notes/components/noteable_discussion.vue';
+import ReplyPlaceholder from '~/notes/components/discussion_reply_placeholder.vue';
 import '~/behaviors/markdown/render_gfm';
 import { noteableDataMock, discussionMock, notesDataMock } from '../mock_data';
 import mockDiffFile from '../../diffs/mock_data/diff_file';
@@ -57,27 +58,23 @@ describe('noteable_discussion component', () => {
   });
 
   describe('actions', () => {
-    it('should render reply button', () => {
-      expect(
-        wrapper
-          .find('.js-vue-discussion-reply')
-          .text()
-          .trim(),
-      ).toEqual('Reply...');
-    });
-
     it('should toggle reply form', done => {
-      wrapper.find('.js-vue-discussion-reply').trigger('click');
+      const replyPlaceholder = wrapper.find(ReplyPlaceholder);
 
-      wrapper.vm.$nextTick(() => {
-        expect(wrapper.vm.isReplying).toEqual(true);
+      wrapper.vm
+        .$nextTick()
+        .then(() => {
+          expect(wrapper.vm.isReplying).toEqual(false);
 
-        // There is a watcher for `isReplying` which will init autosave in the next tick
-        wrapper.vm.$nextTick(() => {
+          replyPlaceholder.vm.$emit('onClick');
+        })
+        .then(() => wrapper.vm.$nextTick())
+        .then(() => {
+          expect(wrapper.vm.isReplying).toEqual(true);
           expect(wrapper.vm.$refs.noteForm).not.toBeNull();
-          done();
-        });
-      });
+        })
+        .then(done)
+        .catch(done.fail);
     });
 
     it('does not render jump to discussion button', () => {