然后在蓝知更鸟中调用函数

Question

我如何才能调用一个函数，然后()呢？我是蓝鸟的新手，以前我只会触发回调，通知被调用的函数是用它的东西完成的。

这是我的“主代码”，它将地区数据插入到我的Mongo和Redis数据库中。

var promise = Language.findOne({}).exec()

promise.then(function(languages) {
    /* If collection is empty initialize it */
    if(!languages)
        return insertLanguagesIntoMongoDB()
})
.then(function() {
    /* Make sure it's cached in Redis */
    return insertLanguagesIntoRedis()
})
.catch(function(err) {
    throw err
})

这是我的函数的样子，但它说“回调不是函数”：

function insertLanguagesIntoRedis(callback) {
    logger.info("Inserting languages into redis db")
    var promise = Language.find({}).exec()
    promise.then(function(languages) {
        if(!languages)
            throw new Error("Couldn't find any languages in MongoDB's Language collection")

        var languageJson = []
        for(var i=0; i<languages.length; i++) {
            var object = {}
            object.id = languages[i].iso_code
            object.text = languages[i].name_en
            languageJson.push(object)
        }
        redis.set('languages', JSON.stringify(languageJson))
        return callback()
    })
    .catch(function (err) {
        throw err
    })
}

那么，如何正确地定义和调用我的insertLanguagesIntoRedis和insertLanguagesIntoMongoDB函数呢？

Answer 1

类似这样的东西可能会起作用：

1. 把语言传递到承诺链中
2. 在链的末尾，将承诺返回到下一步。
3. 调整下一步以接受这些语言
4. 调整insertLanguagesIntoRedis以接受语言
5. 让insertLanguagesIntoRedis返回承诺链
6. 从insertLanguagesIntoRedis中删除回调调用

变量允诺= Language.findOne({}).exec()

promise.then(function(languages) {
    /* If collection is empty initialize it */
    if(!languages)
        insertLanguagesIntoMongoDB()
     return languages
})
.then(function(languages) {
    /* Make sure it's cached in Redis */
    return insertLanguagesIntoRedis(languages)
})
.catch(function(err) {
    throw err
})

function insertLanguagesIntoRedis(languages) {
    logger.info("Inserting languages into redis db")
    var promise = Language.find({}).exec()
    return promise.then(function(languages) {
        if(!languages)
            throw new Error("Couldn't find any languages in MongoDB's Language collection")

        var languageJson = []
        for(var i=0; i<languages.length; i++) {
            var object = {}
            object.id = languages[i].iso_code
            object.text = languages[i].name_en
            languageJson.push(object)
        }
        redis.set('languages', JSON.stringify(languageJson))
    })
    .catch(function (err) {
        throw err
    })
}

更新per @Bergi

var promise = Language.findOne({}).exec()

promise.then(function(languages) {
    /* If collection is empty initialize it */
    if(!languages)
        insertLanguagesIntoMongoDB()
     return languages
})
.then(function(languages) {
    /* Make sure it's cached in Redis */
    return insertLanguagesIntoRedis(languages)
});

function insertLanguagesIntoRedis(languages) {
    logger.info("Inserting languages into redis db")
    var promise = Language.find({}).exec()
    return promise.then(function(languages) {
        if(!languages)
            throw new Error("Couldn't find any languages in MongoDB's Language collection")

        var languageJson = []
        for(var i=0; i<languages.length; i++) {
            var object = {}
            object.id = languages[i].iso_code
            object.text = languages[i].name_en
            languageJson.push(object)
        }
        redis.set('languages', JSON.stringify(languageJson))
    })
}