index.js

import { VantComponent } from '../common/component';
import { addUnit, getRect, getSystemInfoSync } from '../common/utils';
let ARRAY = [];
VantComponent({
  field: true,
  relation: {
    name: 'dropdown-item',
    type: 'descendant',
    current: 'dropdown-menu',
    linked() {
      this.updateItemListData();
    },
    unlinked() {
      this.updateItemListData();
    },
  },
  props: {
    activeColor: {
      type: String,
      observer: 'updateChildrenData',
    },
    overlay: {
      type: Boolean,
      value: true,
      observer: 'updateChildrenData',
    },
    zIndex: {
      type: Number,
      value: 10,
    },
    duration: {
      type: Number,
      value: 200,
      observer: 'updateChildrenData',
    },
    direction: {
      type: String,
      value: 'down',
      observer: 'updateChildrenData',
    },
    closeOnClickOverlay: {
      type: Boolean,
      value: true,
      observer: 'updateChildrenData',
    },
    closeOnClickOutside: {
      type: Boolean,
      value: true,
    },
  },
  data: {
    itemListData: [],
  },
  beforeCreate() {
    const { windowHeight } = getSystemInfoSync();
    this.windowHeight = windowHeight;
    ARRAY.push(this);
  },
  destroyed() {
    ARRAY = ARRAY.filter((item) => item !== this);
  },
  methods: {
    updateItemListData() {
      this.setData({
        itemListData: this.children.map((child) => child.data),
      });
    },
    updateChildrenData() {
      this.children.forEach((child) => {
        child.updateDataFromParent();
      });
    },
    toggleItem(active) {
      this.children.forEach((item, index) => {
        const { showPopup } = item.data;
        if (index === active) {
          item.toggle();
        } else if (showPopup) {
          item.toggle(false, { immediate: true });
        }
      });
    },
    close() {
      this.children.forEach((child) => {
        child.toggle(false, { immediate: true });
      });
    },
    getChildWrapperStyle() {
      const { zIndex, direction } = this.data;
      return getRect(this, '.van-dropdown-menu').then((rect) => {
        const { top = 0, bottom = 0 } = rect;
        const offset = direction === 'down' ? bottom : this.windowHeight - top;
        let wrapperStyle = `z-index: ${zIndex};`;
        if (direction === 'down') {
          wrapperStyle += `top: ${addUnit(offset)};`;
        } else {
          wrapperStyle += `bottom: ${addUnit(offset)};`;
        }
        return wrapperStyle;
      });
    },
    onTitleTap(event) {
      const { index } = event.currentTarget.dataset;
      const child = this.children[index];
      if (!child.data.disabled) {
        ARRAY.forEach((menuItem) => {
          if (
            menuItem &&
            menuItem.data.closeOnClickOutside &&
            menuItem !== this
          ) {
            menuItem.close();
          }
        });
        this.toggleItem(index);
      }
    },
  },
});