bootstrap-vue/esm/mixins/dropdown.js

With more than 85 components, over 45 available plugins, several directives, and 1000+ icons, BootstrapVue provides one of the most comprehensive implementations of the Bootstrap v4 component and grid system available for Vue.js v2.6, complete with extens

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import Popper from 'popper.js';
import { extend } from '../vue';
import { NAME_DROPDOWN } from '../constants/components';
import { HAS_TOUCH_SUPPORT } from '../constants/env';
import { EVENT_NAME_CLICK, EVENT_NAME_HIDDEN, EVENT_NAME_HIDE, EVENT_NAME_SHOW, EVENT_NAME_SHOWN, EVENT_NAME_TOGGLE } from '../constants/events';
import { CODE_DOWN, CODE_ENTER, CODE_ESC, CODE_SPACE, CODE_UP } from '../constants/key-codes';
import { PLACEMENT_TOP_START, PLACEMENT_TOP_END, PLACEMENT_BOTTOM_START, PLACEMENT_BOTTOM_END, PLACEMENT_RIGHT_START, PLACEMENT_LEFT_START } from '../constants/popper';
import { PROP_TYPE_BOOLEAN, PROP_TYPE_NUMBER_STRING, PROP_TYPE_OBJECT, PROP_TYPE_STRING } from '../constants/props';
import { HTMLElement } from '../constants/safe-types';
import { BvEvent } from '../utils/bv-event.class';
import { attemptFocus, closest, contains, isVisible, requestAF, selectAll } from '../utils/dom';
import { getRootEventName, stopEvent } from '../utils/events';
import { isNull } from '../utils/inspect';
import { mergeDeep, sortKeys } from '../utils/object';
import { makeProp, makePropsConfigurable } from '../utils/props';
import { warn } from '../utils/warn';
import { clickOutMixin } from './click-out';
import { focusInMixin } from './focus-in';
import { idMixin, props as idProps } from './id';
import { listenOnRootMixin } from './listen-on-root';
import { registerElementToInstance, removeElementToInstance } from '../utils/element-to-vue-instance-registry'; // --- Constants ---

var ROOT_EVENT_NAME_SHOWN = getRootEventName(NAME_DROPDOWN, EVENT_NAME_SHOWN);
var ROOT_EVENT_NAME_HIDDEN = getRootEventName(NAME_DROPDOWN, EVENT_NAME_HIDDEN); // CSS selectors

var SELECTOR_FORM_CHILD = '.dropdown form';
var SELECTOR_ITEM = ['.dropdown-item', '.b-dropdown-form'].map(function (selector) {
  return "".concat(selector, ":not(.disabled):not([disabled])");
}).join(', '); // --- Helper methods ---
// Return an array of visible items

var filterVisibles = function filterVisibles(els) {
  return (els || []).filter(isVisible);
}; // --- Props ---


export var props = makePropsConfigurable(sortKeys(_objectSpread(_objectSpread({}, idProps), {}, {
  // String: `scrollParent`, `window` or `viewport`
  // HTMLElement: HTML Element reference
  boundary: makeProp([HTMLElement, PROP_TYPE_STRING], 'scrollParent'),
  disabled: makeProp(PROP_TYPE_BOOLEAN, false),
  // Place left if possible
  dropleft: makeProp(PROP_TYPE_BOOLEAN, false),
  // Place right if possible
  dropright: makeProp(PROP_TYPE_BOOLEAN, false),
  // Place on top if possible
  dropup: makeProp(PROP_TYPE_BOOLEAN, false),
  // Disable auto-flipping of menu from bottom <=> top
  noFlip: makeProp(PROP_TYPE_BOOLEAN, false),
  // Number of pixels or a CSS unit value to offset menu
  // (i.e. `1px`, `1rem`, etc.)
  offset: makeProp(PROP_TYPE_NUMBER_STRING, 0),
  popperOpts: makeProp(PROP_TYPE_OBJECT, {}),
  // Right align menu (default is left align)
  right: makeProp(PROP_TYPE_BOOLEAN, false)
})), NAME_DROPDOWN); // --- Mixin ---
// @vue/component

export var dropdownMixin = extend({
  mixins: [idMixin, listenOnRootMixin, clickOutMixin, focusInMixin],
  provide: function provide() {
    var _this = this;

    return {
      getBvDropdown: function getBvDropdown() {
        return _this;
      }
    };
  },
  inject: {
    getBvNavbar: {
      default: function _default() {
        return function () {
          return null;
        };
      }
    }
  },
  props: props,
  data: function data() {
    return {
      visible: false,
      visibleChangePrevented: false
    };
  },
  computed: {
    bvNavbar: function bvNavbar() {
      return this.getBvNavbar();
    },
    inNavbar: function inNavbar() {
      return !isNull(this.bvNavbar);
    },
    toggler: function toggler() {
      var toggle = this.$refs.toggle;
      return toggle ? toggle.$el || toggle : null;
    },
    directionClass: function directionClass() {
      if (this.dropup) {
        return 'dropup';
      } else if (this.dropright) {
        return 'dropright';
      } else if (this.dropleft) {
        return 'dropleft';
      }

      return '';
    },
    boundaryClass: function boundaryClass() {
      // Position `static` is needed to allow menu to "breakout" of the `scrollParent`
      // boundaries when boundary is anything other than `scrollParent`
      // See: https://github.com/twbs/bootstrap/issues/24251#issuecomment-341413786
      return this.boundary !== 'scrollParent' && !this.inNavbar ? 'position-static' : '';
    },
    hideDelay: function hideDelay() {
      return this.inNavbar ? HAS_TOUCH_SUPPORT ? 300 : 50 : 0;
    }
  },
  watch: {
    visible: function visible(newValue, oldValue) {
      if (this.visibleChangePrevented) {
        this.visibleChangePrevented = false;
        return;
      }

      if (newValue !== oldValue) {
        var eventName = newValue ? EVENT_NAME_SHOW : EVENT_NAME_HIDE;
        var bvEvent = new BvEvent(eventName, {
          cancelable: true,
          vueTarget: this,
          target: this.$refs.menu,
          relatedTarget: null,
          componentId: this.safeId ? this.safeId() : this.id || null
        });
        this.emitEvent(bvEvent);

        if (bvEvent.defaultPrevented) {
          // Reset value and exit if canceled
          this.visibleChangePrevented = true;
          this.visible = oldValue; // Just in case a child element triggered `this.hide(true)`

          this.$off(EVENT_NAME_HIDDEN, this.focusToggler);
          return;
        }

        if (newValue) {
          this.showMenu();
        } else {
          this.hideMenu();
        }
      }
    },
    disabled: function disabled(newValue, oldValue) {
      if (newValue !== oldValue && newValue && this.visible) {
        // Hide dropdown if disabled changes to true
        this.visible = false;
      }
    }
  },
  created: function created() {
    // Create private non-reactive props
    this.$_popper = null;
    this.$_hideTimeout = null;
  },

  /* istanbul ignore next */
  deactivated: function deactivated() {
    // In case we are inside a `<keep-alive>`
    this.visible = false;
    this.whileOpenListen(false);
    this.destroyPopper();
  },
  mounted: function mounted() {
    registerElementToInstance(this.$el, this);
  },
  beforeDestroy: function beforeDestroy() {
    this.visible = false;
    this.whileOpenListen(false);
    this.destroyPopper();
    this.clearHideTimeout();
    removeElementToInstance(this.$el);
  },
  methods: {
    // Event emitter
    emitEvent: function emitEvent(bvEvent) {
      var type = bvEvent.type;
      this.emitOnRoot(getRootEventName(NAME_DROPDOWN, type), bvEvent);
      this.$emit(type, bvEvent);
    },
    showMenu: function showMenu() {
      var _this2 = this;

      if (this.disabled) {
        /* istanbul ignore next */
        return;
      } // Only instantiate Popper.js when dropdown is not in `<b-navbar>`


      if (!this.inNavbar) {
        if (typeof Popper === 'undefined') {
          /* istanbul ignore next */
          warn('Popper.js not found. Falling back to CSS positioning', NAME_DROPDOWN);
        } else {
          // For dropup with alignment we use the parent element as popper container
          var el = this.dropup && this.right || this.split ? this.$el : this.$refs.toggle; // Make sure we have a reference to an element, not a component!

          el = el.$el || el; // Instantiate Popper.js

          this.createPopper(el);
        }
      } // Ensure other menus are closed


      this.emitOnRoot(ROOT_EVENT_NAME_SHOWN, this); // Enable listeners

      this.whileOpenListen(true); // Wrap in `$nextTick()` to ensure menu is fully rendered/shown

      this.$nextTick(function () {
        // Focus on the menu container on show
        _this2.focusMenu(); // Emit the shown event


        _this2.$emit(EVENT_NAME_SHOWN);
      });
    },
    hideMenu: function hideMenu() {
      this.whileOpenListen(false);
      this.emitOnRoot(ROOT_EVENT_NAME_HIDDEN, this);
      this.$emit(EVENT_NAME_HIDDEN);
      this.destroyPopper();
    },
    createPopper: function createPopper(element) {
      this.destroyPopper();
      this.$_popper = new Popper(element, this.$refs.menu, this.getPopperConfig());
    },
    // Ensure popper event listeners are removed cleanly
    destroyPopper: function destroyPopper() {
      this.$_popper && this.$_popper.destroy();
      this.$_popper = null;
    },
    // Instructs popper to re-computes the dropdown position
    // useful if the content changes size
    updatePopper: function updatePopper() {
      try {
        this.$_popper.scheduleUpdate();
      } catch (_unused) {}
    },
    clearHideTimeout: function clearHideTimeout() {
      clearTimeout(this.$_hideTimeout);
      this.$_hideTimeout = null;
    },
    getPopperConfig: function getPopperConfig() {
      var placement = PLACEMENT_BOTTOM_START;

      if (this.dropup) {
        placement = this.right ? PLACEMENT_TOP_END : PLACEMENT_TOP_START;
      } else if (this.dropright) {
        placement = PLACEMENT_RIGHT_START;
      } else if (this.dropleft) {
        placement = PLACEMENT_LEFT_START;
      } else if (this.right) {
        placement = PLACEMENT_BOTTOM_END;
      }

      var popperConfig = {
        placement: placement,
        modifiers: {
          offset: {
            offset: this.offset || 0
          },
          flip: {
            enabled: !this.noFlip
          }
        }
      };
      var boundariesElement = this.boundary;

      if (boundariesElement) {
        popperConfig.modifiers.preventOverflow = {
          boundariesElement: boundariesElement
        };
      }

      return mergeDeep(popperConfig, this.popperOpts || {});
    },
    // Turn listeners on/off while open
    whileOpenListen: function whileOpenListen(isOpen) {
      // Hide the dropdown when clicked outside
      this.listenForClickOut = isOpen; // Hide the dropdown when it loses focus

      this.listenForFocusIn = isOpen; // Hide the dropdown when another dropdown is opened

      var method = isOpen ? 'listenOnRoot' : 'listenOffRoot';
      this[method](ROOT_EVENT_NAME_SHOWN, this.rootCloseListener);
    },
    rootCloseListener: function rootCloseListener(vm) {
      if (vm !== this) {
        this.visible = false;
      }
    },
    // Public method to show dropdown
    show: function show() {
      var _this3 = this;

      if (this.disabled) {
        return;
      } // Wrap in a `requestAF()` to allow any previous
      // click handling to occur first


      requestAF(function () {
        _this3.visible = true;
      });
    },
    // Public method to hide dropdown
    hide: function hide() {
      var refocus = arguments.length > 0 && arguments[0] !== undefined ? arguments[0] : false;

      /* istanbul ignore next */
      if (this.disabled) {
        return;
      }

      this.visible = false;

      if (refocus) {
        // Child element is closing the dropdown on click
        this.$once(EVENT_NAME_HIDDEN, this.focusToggler);
      }
    },
    // Called only by a button that toggles the menu
    toggle: function toggle(event) {
      event = event || {}; // Early exit when not a click event or ENTER, SPACE or DOWN were pressed

      var _event = event,
          type = _event.type,
          keyCode = _event.keyCode;

      if (type !== 'click' && !(type === 'keydown' && [CODE_ENTER, CODE_SPACE, CODE_DOWN].indexOf(keyCode) !== -1)) {
        /* istanbul ignore next */
        return;
      }
      /* istanbul ignore next */


      if (this.disabled) {
        this.visible = false;
        return;
      }

      this.$emit(EVENT_NAME_TOGGLE, event);
      stopEvent(event); // Toggle visibility

      if (this.visible) {
        this.hide(true);
      } else {
        this.show();
      }
    },
    // Mousedown handler for the toggle

    /* istanbul ignore next */
    onMousedown: function onMousedown(event) {
      // We prevent the 'mousedown' event for the toggle to stop the
      // 'focusin' event from being fired
      // The event would otherwise be picked up by the global 'focusin'
      // listener and there is no cross-browser solution to detect it
      // relates to the toggle click
      // The 'click' event will still be fired and we handle closing
      // other dropdowns there too
      // See https://github.com/bootstrap-vue/bootstrap-vue/issues/4328
      stopEvent(event, {
        propagation: false
      });
    },
    // Called from dropdown menu context
    onKeydown: function onKeydown(event) {
      var keyCode = event.keyCode;

      if (keyCode === CODE_ESC) {
        // Close on ESC
        this.onEsc(event);
      } else if (keyCode === CODE_DOWN) {
        // Down Arrow
        this.focusNext(event, false);
      } else if (keyCode === CODE_UP) {
        // Up Arrow
        this.focusNext(event, true);
      }
    },
    // If user presses ESC, close the menu
    onEsc: function onEsc(event) {
      if (this.visible) {
        this.visible = false;
        stopEvent(event); // Return focus to original trigger button

        this.$once(EVENT_NAME_HIDDEN, this.focusToggler);
      }
    },
    // Called only in split button mode, for the split button
    onSplitClick: function onSplitClick(event) {
      /* istanbul ignore next */
      if (this.disabled) {
        this.visible = false;
        return;
      }

      this.$emit(EVENT_NAME_CLICK, event);
    },
    // Shared hide handler between click-out and focus-in events
    hideHandler: function hideHandler(event) {
      var _this4 = this;

      var target = event.target;

      if (this.visible && !contains(this.$refs.menu, target) && !contains(this.toggler, target)) {
        this.clearHideTimeout();
        this.$_hideTimeout = setTimeout(function () {
          return _this4.hide();
        }, this.hideDelay);
      }
    },
    // Document click-out listener
    clickOutHandler: function clickOutHandler(event) {
      this.hideHandler(event);
    },
    // Document focus-in listener
    focusInHandler: function focusInHandler(event) {
      this.hideHandler(event);
    },
    // Keyboard nav
    focusNext: function focusNext(event, up) {
      var _this5 = this;

      // Ignore key up/down on form elements
      var target = event.target;

      if (!this.visible || event && closest(SELECTOR_FORM_CHILD, target)) {
        /* istanbul ignore next: should never happen */
        return;
      }

      stopEvent(event);
      this.$nextTick(function () {
        var items = _this5.getItems();

        if (items.length < 1) {
          /* istanbul ignore next: should never happen */
          return;
        }

        var index = items.indexOf(target);

        if (up && index > 0) {
          index--;
        } else if (!up && index < items.length - 1) {
          index++;
        }

        if (index < 0) {
          /* istanbul ignore next: should never happen */
          index = 0;
        }

        _this5.focusItem(index, items);
      });
    },
    focusItem: function focusItem(index, items) {
      var el = items.find(function (el, i) {
        return i === index;
      });
      attemptFocus(el);
    },
    getItems: function getItems() {
      // Get all items
      return filterVisibles(selectAll(SELECTOR_ITEM, this.$refs.menu));
    },
    focusMenu: function focusMenu() {
      attemptFocus(this.$refs.menu);
    },
    focusToggler: function focusToggler() {
      var _this6 = this;

      this.$nextTick(function () {
        attemptFocus(_this6.toggler);
      });
    }
  }
});