Use bootstrap dropdown events to only make the request when the dropdown is being opened

Fixes builds dropdown making request when clicked to be closed

Adds MR ID to CHANGELOG

Improve documentation

Use bootstrap dropdown events to only make the request when the dropdown is being opened

app/assets/javascripts/mini_pipeline_graph_dropdown.js.es6

@@ -10,9 +10,9 @@
  * The container should be the table element.
  *
  * The stage icon clicked needs to have the following HTML structure:
- * <div>
- *   <button class="dropdown js-builds-dropdown-button"></button>
- *   <div class="js-builds-dropdown-container"></div>
+ * <div class="dropdown">
+ *   <button class="dropdown js-builds-dropdown-button" data-toggle="dropdown"></button>
+ *   <div class="js-builds-dropdown-container dropdown-menu"></div>
  * </div>
  */
 (() => {
@@ -26,13 +26,11 @@
     }
 
     /**
-     * Adds and removes the event listener.
+     * Adds the event listener when the dropdown is opened.
+     * All dropdown events are fired at the .dropdown-menu's parent element.
      */
     bindEvents() {
-      const dropdownButtonSelector = 'button.js-builds-dropdown-button';
-
-      $(this.container).off('click', dropdownButtonSelector, this.getBuildsList)
-        .on('click', dropdownButtonSelector, this.getBuildsList);
+      $(this.container).on('shown.bs.dropdown', this.getBuildsList);
     }
 
     /**
@@ -52,11 +50,14 @@
     /**
      * For the clicked stage, gets the list of builds.
      *
-     * @param  {Object} e
+     * All dropdown events have a relatedTarget property,
+     * whose value is the toggling anchor element.
+     *
+     * @param  {Object} e bootstrap dropdown event
      * @return {Promise}
      */
     getBuildsList(e) {
-      const button = e.currentTarget;
+      const button = e.relatedTarget;
       const endpoint = button.dataset.stageEndpoint;
 
       return $.ajax({

changelogs/unreleased/26601-dropdown-makes-request-close.yml

+---
+title: Fixes builds dropdown making request when clicked to be closed
+merge_request: 8545
+author:

spec/javascripts/fixtures/mini_dropdown_graph.html.haml

-%div.js-builds-dropdown-tests
-  %button.dropdown.js-builds-dropdown-button{'data-stage-endpoint' => 'foobar'}
+%div.js-builds-dropdown-tests.dropdown.dropdown.js-mini-pipeline-graph
+  %button.js-builds-dropdown-button{'data-stage-endpoint' => 'foobar', data: { toggle: 'dropdown'} }
     Dropdown
-  %div.js-builds-dropdown-container
-    %div.js-builds-dropdown-list
 
-    %div.js-builds-dropdown-loading.builds-dropdown-loading.hidden
+  %ul.dropdown-menu.mini-pipeline-graph-dropdown-menu.js-builds-dropdown-container
+    .js-builds-dropdown-list.scrollable-menu
+
+    .js-builds-dropdown-loading.builds-dropdown-loading.hidden
       %span.fa.fa-spinner.fa-spin