vant-weapp/packages/nav-bar/demo/index.ts

import { VantComponent } from '../../common/component';

VantComponent({
  methods: {
    onClickLeft() {
      wx.showToast({ title: '点击返回', icon: 'none' });
    },

    onClickRight() {
      wx.showToast({ title: '点击按钮', icon: 'none' });
    },
  },
});