// app.js

const initStore = {
    hasLogin: false,
    userName: ''
}
const { createStore } = require('miniprogram-sync-state')
const Store = createStore(initStore)

App({
    onLaunch() {},
    Store
})

// pages/login/index.js

let app = getApp()
const { connect } = app.Store

const LoginPage = {
    onReady(e) {},
    onShow() {},
    bindUserNameChange(e) {
        this.setData({
            username: e.detail.value
        })
    },
    bindLogin() {
        if (!this.data.username) return
        this.login(this.data.username)
        wx.navigateBack({
            delta: 1
        })
    }
}
const ConnectPage = connect(
    ({ hasLogin, userName }) => {
        return {
            hasLogin,
            userName
        }
    },
    (setState, state) => ({
        login(userName) {
            setState({
                hasLogin: true,
                userName
            })
        }
    })
)(LoginPage)

Page(ConnectPage)

// 🚫 以下为禁止示例

const ConnectPage = connect(state => {
    state.userInfo.userName = 'err use'
    return {
        userInfo: state.userInfo
    }
})(Page)