import { VantComponent } from '../common/component'; import { useChildren } from '../common/relation'; VantComponent({ relation: useChildren('sidebar-item', function () { this.setActive(this.data.activeKey); }), props: { activeKey: { type: Number, value: 0, observer: 'setActive', }, }, beforeCreate() { 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); }, }, });