[skip ci] use assigneeDropdown ref

app/assets/javascripts/boards/components/board_sidebar.js

@@ -47,7 +47,9 @@ require('./sidebar/remove_issue');
           this.issue = this.detail.issue;
           this.list = this.detail.list;
 
-          this.endpoint = this.$el.querySelector('.js-user-search').dataset.issueUpdate;
+          this.$nextTick(() => {
+            this.endpoint = this.$refs.assigneeDropdown.dataset.issueUpdate;
+          });
         },
         deep: true
       },

app/views/projects/boards/components/sidebar/_assignee.html.haml

@@ -15,7 +15,7 @@
         "v-if" => "issue.assignees",
         "v-for" => "assignee in issue.assignees" }
       .dropdown
-        %button.dropdown-menu-toggle.js-user-search.js-author-search.js-multiselect.js-save-user-data.js-issue-board-sidebar{ type: "button", data: { toggle: "dropdown", field_name: "issue[assignee_ids][]", first_user: (current_user.username if current_user), current_user: "true", project_id: @project.id, null_user: "true", multi_select: "true", dropdown: { header: 'Assignee(s)'} },
+        %button.dropdown-menu-toggle.js-user-search.js-author-search.js-multiselect.js-save-user-data.js-issue-board-sidebar{ type: "button", ref: "assigneeDropdown", data: { toggle: "dropdown", field_name: "issue[assignee_ids][]", first_user: (current_user.username if current_user), current_user: "true", project_id: @project.id, null_user: "true", multi_select: "true", dropdown: { header: 'Assignee(s)'} },
           ":data-issuable-id" => "issue.id",
           ":data-issue-update" => "'#{namespace_project_issues_path(@project.namespace, @project)}/' + issue.id + '.json'" }
           Select assignee(s)