Mongoose 模型的 Mocha 测试产生“then”错误

Question

我正在运行 API 的早期测试，错误应该很明显，但我在 45 分钟内一直盯着相同的代码看。

这是错误

Creating User document find or create a twitter user:
TypeError: Cannot read property 'then' of undefined

这是测试。错误在于 .then(user=> {...}

行

const assert = require('assert');
const User = require('../models/userModel');
const userController = require('../controllers/usersController');

describe('Creating User document', () => {
    it('find or create a twitter user', (done) => {
            userController.findOrCreateHelper({
                username : 'testuser', 
                displayName : 'testUserDisplay', 
                id : 111000100, 
                provider : 'Twitter'
                })
                .then(user => {
                    console.log('*** Error in this .then bracket ***', user)
                    assert(user === 'testuser')
                    assert(user.id === 111000100)
                    done()
                }).catch(error => console.error(error))
    })

这是控制器

const mongoose = require('mongoose');
const User = require('../models/userModel');

exports.findUser = ({id}) => {
    return User.findOne({id})
}

exports.createUser = ({username, displayName, id, provider}) => {
    return User.create( {username, displayName, id, provider })
}

exports.findOrCreateHelper = (provider) => {
    exports.findUser({id})
        .then(user => {
            if ( !user ) {
                exports.createUser(provider)
            }
        })
}

Answer 1

exports.findOrCreateHelper 需要“返回 exports.findUser({...}}...”，如下所示：

exports.findOrCreateHelper = (provider) => {
    return exports.findUser({id})
        .then(user => {
            if ( !user ) {
                exports.createUser(provider)
            }
        })
}