老师好，我用的是controller和model,router的文件结构,因此我先在controller中声明了一个类包含了两个方法，再new一个类出来，这里有个问题就是我类中函数相互引用按道理用this指向就可以，但是这里控制台报错了，说getMenuList方法识别不出，也就是this指向无效，能问问怎么解决吗

class UsersCTl {
async getPermissionList(ctx){
const token = ctx.header.authorization
let userInfo = util.decoded(token)
let menuList = getMenuList(userInfo.charater, userInfo.roleList);
ctx.body = util.success({ menuList });
}

async getMenuList(charater, roleKeys) {
    let rootList = []
    if (charater == 0) {
        rootList = await Menu.find({}) || []
    } else {
        // 根据用户拥有的角色，获取权限列表
        // 现查找用户对应的角色有哪些
        let roleList = await Role.find({ _id: { $in: roleKeys } })
        let permissionList = []
        roleList.map(role => {
        let { checkedKeys, halfCheckedKeys } = role.permissionList;
        permissionList = permissionList.concat([...checkedKeys, ...halfCheckedKeys])
        })
        permissionList = [...new Set(permissionList)]
        rootList = await Menu.find({ _id: { $in: permissionList } })
    }
    return util.getTreeMenu(rootList, null, [])
}
}

module.exports = new UsersCTl()

没有侦测到错误抛出
第一次经过jwt
errohandler检测到错误
err.message是Cannot read property ‘getMenuList’ of undefined
err.status是undefined
ctx.status是404
[2021-06-23T09:44:07.346] [ERROR] error - /users/getPermissionList GET 404 TypeError: Cannot read property ‘getMenuList’ of undefined
at getPermissionList (D:\项目\服务端\test\controllers/users.js:145:29)
at dispatch (D:\项目\服务端\test\node_modules\koa-compose\index.js:42:32)
at jwt (D:\项目\服务端\test\node_modules\koa-jwt\lib\index.js:73:16)
at auth (D:\项目\服务端\test\controllers/jwt.js:23:9)
at errorhandler (D:\项目\服务端\test\common/ErrorHandle.js:11:9)
at D:\项目\服务端\test\node_modules\koa-log4\koa-logger.js:86:7
at D:\项目\服务端\test/app.js:70:3
at serve (D:\项目\服务端\test\node_modules\koa-static\index.js:53:9)
at logger (D:\项目\服务端\test\node_modules\koa-logger\index.js:67:7)
at verifyParam (D:\项目\服务端\test\node_modules\koa-parameter\index.js:52:7)
at logger1 (D:\项目\服务端\test\common/Logger.js:7:5)
at cors (D:\项目\服务端\test\node_modules\koa2-cors\dist\index.js:91:9)
at serve (D:\项目\服务端\test\node_modules\koa-static\index.js:53:9)
我就搞不明白了