deguodaigou/utils/dist/sidebar/index.js

import { VantComponent } from '../common/component';
VantComponent({
    relation: {
        name: 'sidebar-item',
        type: 'descendant',
        linked(target) {
            this.children.push(target);
            this.setActive(this.data.activeKey);
        },
        unlinked(target) {
            this.children = this.children.filter((item) => item !== target);
            this.setActive(this.data.activeKey);
        }
    },
    props: {
        activeKey: {
            type: Number,
            value: 0,
            observer: 'setActive'
        }
    },
    beforeCreate() {
        this.children = [];
        this.currentActive = -1;
    },
    methods: {
        setActive(activeKey) {
            const { children, currentActive } = this;
            if (!children.length) {
                return Promise.resolve();
            }
            this.currentActive = activeKey;
            const stack = [];
            if (currentActive !== activeKey && children[currentActive]) {
                stack.push(children[currentActive].setActive(false));
            }
            if (children[activeKey]) {
                stack.push(children[activeKey].setActive(true));
            }
            return Promise.all(stack);
        }
    }
});