Fixes ajax requests when current URL has a trailing slash

app/assets/javascripts/filtered_search/filtered_search_dropdown_manager.js.es6

@@ -2,7 +2,8 @@
 
 (() => {
   class FilteredSearchDropdownManager {
-    constructor() {
+    constructor(baseEndpoint = '') {
+      this.baseEndpoint = baseEndpoint.replace(/\/$/, '');
       this.tokenizer = gl.FilteredSearchTokenizer;
       this.filteredSearchInput = document.querySelector('.filtered-search');
 
@@ -38,13 +39,13 @@
         milestone: {
           reference: null,
           gl: 'DropdownNonUser',
-          extraArguments: ['milestones.json', '%'],
+          extraArguments: [`${this.baseEndpoint}/milestones.json`, '%'],
           element: document.querySelector('#js-dropdown-milestone'),
         },
         label: {
           reference: null,
           gl: 'DropdownNonUser',
-          extraArguments: ['labels.json', '~'],
+          extraArguments: [`${this.baseEndpoint}/labels.json`, '~'],
           element: document.querySelector('#js-dropdown-label'),
         },
         hint: {

app/assets/javascripts/filtered_search/filtered_search_manager.js.es6

@@ -6,7 +6,7 @@
 
       if (this.filteredSearchInput) {
         this.tokenizer = gl.FilteredSearchTokenizer;
-        this.dropdownManager = new gl.FilteredSearchDropdownManager();
+        this.dropdownManager = new gl.FilteredSearchDropdownManager(this.filteredSearchInput.getAttribute('data-base-endpoint'));
 
         this.bindEvents();
         this.loadSearchParamsFromURL();

app/views/shared/issuable/_search_bar.html.haml

@@ -11,7 +11,7 @@
             class: "check_all_issues left"
       .issues-other-filters.filtered-search-container
         .filtered-search-input-container
-          %input.form-control.filtered-search{ placeholder: 'Search or filter results...', 'data-id' => 'filtered-search', 'data-project-id' => @project.id, 'data-username-params' => @users.to_json(only: [:id, :username]) }
+          %input.form-control.filtered-search{ placeholder: 'Search or filter results...', 'data-id' => 'filtered-search', 'data-project-id' => @project.id, 'data-username-params' => @users.to_json(only: [:id, :username]), 'data-base-endpoint' => namespace_project_path(@project.namespace, @project) }
           = icon('filter')
           %button.clear-search.hidden{ type: 'button' }
             = icon('times')