diff --git a/docs/4.0/components/dropdowns.md b/docs/4.0/components/dropdowns.md index cde123b00c41..926729a3d9ab 100644 --- a/docs/4.0/components/dropdowns.md +++ b/docs/4.0/components/dropdowns.md @@ -723,9 +723,17 @@ Options can be passed via data attributes or JavaScript. For data attributes, ap true Allow Dropdown to flip in case of an overlapping on the reference element. For more information refer to Popper.js's flip docs. + + boundary + string | element + 'scrollParent' + Overflow constraint boundary of the dropdown menu. Accepts the values of 'viewport', 'window', 'scrollParent', or an HTMLElement reference (JavaScript only). For more information refer to Popper.js's preventOverflow docs. + +Note when `boundary` is set to any value other than `'scrollParent'`, the style `position: static` is applied to the `.dropdown` container. + ### Methods | Method | Description | diff --git a/js/src/dropdown.js b/js/src/dropdown.js index 8affedc6ce9e..56559b434576 100644 --- a/js/src/dropdown.js +++ b/js/src/dropdown.js @@ -50,7 +50,8 @@ const Dropdown = (($) => { DROPRIGHT : 'dropright', DROPLEFT : 'dropleft', MENURIGHT : 'dropdown-menu-right', - MENULEFT : 'dropdown-menu-left' + MENULEFT : 'dropdown-menu-left', + POSITION_STATIC : 'position-static' } const Selector = { @@ -74,12 +75,14 @@ const Dropdown = (($) => { const Default = { offset : 0, - flip : true + flip : true, + boundary : 'scrollParent' } const DefaultType = { offset : '(number|string|function)', - flip : 'boolean' + flip : 'boolean', + boundary : '(string|element)' } @@ -159,6 +162,12 @@ const Dropdown = (($) => { element = parent } } + // If boundary is not `scrollParent`, then set position to `static` + // to allow the menu to "escape" the scroll parent's boundaries + // https://github.com/twbs/bootstrap/issues/24251 + if (this._config.boundary !== 'scrollParent') { + $(parent).addClass(ClassName.POSITION_STATIC) + } this._popper = new Popper(element, this._menu, this._getPopperConfig()) } @@ -276,6 +285,9 @@ const Dropdown = (($) => { offset : offsetConf, flip : { enabled : this._config.flip + }, + preventOverflow : { + boundariesElement : this._config.boundary } } } diff --git a/js/tests/unit/dropdown.js b/js/tests/unit/dropdown.js index c1202266b13d..41c53a98ad84 100644 --- a/js/tests/unit/dropdown.js +++ b/js/tests/unit/dropdown.js @@ -67,6 +67,50 @@ $(function () { $dropdown.trigger($.Event('click')) }) + QUnit.test('should not add class position-static to dropdown if boundary not set', function (assert) { + assert.expect(1) + var done = assert.async() + var dropdownHTML = '
' + + '' + + '
' + var $dropdown = $(dropdownHTML).find('[data-toggle="dropdown"]').bootstrapDropdown() + $dropdown + .parent('.dropdown') + .on('shown.bs.dropdown', function () { + assert.ok(!$dropdown.parent('.dropdown').hasClass('position-static'), '"position-static" class not added') + done() + }) + $dropdown.trigger('click') + }) + + QUnit.test('should add class position-static to dropdown if boundary not scrollParent', function (assert) { + assert.expect(1) + var done = assert.async() + var dropdownHTML = '
' + + '' + + '
' + var $dropdown = $(dropdownHTML).find('[data-toggle="dropdown"]').bootstrapDropdown() + $dropdown + .parent('.dropdown') + .on('shown.bs.dropdown', function () { + assert.ok($dropdown.parent('.dropdown').hasClass('position-static'), '"position-static" class added') + done() + }) + $dropdown.trigger('click') + }) + QUnit.test('should set aria-expanded="true" on target when dropdown menu is shown', function (assert) { assert.expect(1) var done = assert.async()