.then()在上一个.then(

Question

我正在从本地销售点数据库(第三方软件(中提取类别信息，并试图将其写入WooCommerce商店。我还将数据存储到自己的数据库中，以维护两个系统之间的关系。我使用promise对所有内容进行排序，但我的一个.then((语句在前一个.ten((返回之前就已经启动了，所以我向WooCommerce发送了一个空的有效负载。

router.post("/:action", (req, res) => {
if(req.params.action === "sync" && req.body.action === "sync") {
// Query the POS database
mssql.query(query, (err, result) => {
let postData = {
create: [],
update: []
}
// Make some promises to pull the POS categories and their children
Promise.all(promises)
.then(cats => {
let catPromises = cats.map(cat => {
return new Promise((resolve, reject) => {
Category.findOne(
// Check for existing entry in the linking DB...
)
.then(data => {
// ...and handle accordingly
resolve()
})
.then(() => {
let childPromises = cat.children.map(child => {
return new Promise((resolve, reject) => {
Category.findOne(
// Checking for existing entry in the linking DB...
)
.then(data => {
// ...and handle accordingly
resolve()
})
})
})
Promise.all(childPromises)
.then(resolved => {
resolve()
})
})
})
})
Promise.all(catPromises)
.then(() => {
return
})
})
.then(() => {
// This is the part that's firing early
return axios.post(
// data
)
})
...

编辑：新重构，仍然存在问题。

Promise.all(promises).then(cats => {
let catPromises = cats.map(cat => {
Category.findOne(
// Check for existing...
).then(data => {
// ...and handle accordingly
}).then(() => {
let childPromises = cat.children.map(child => {
Category.findOne(
// Check for existing...
).then(data => {
// ...and handle accordingly
})
})
return Promise.all(childPromises)
})
})
// Now this is where we're reaching early
return Promise.all(catPromises)
}).then(() => {
// API call
})

Answer 1

最终解决方案：

Promise.all(promises).then(cats => {
let catPromises = cats.map(cat => {
return Category.findOne(
// Check for existing...
).then(data => {
// ...and handle accordingly
}).then(() => {
let childPromises = cat.children.map(child => {
return Category.findOne(
// Check for existing...
).then(data => {
// ...and handle accordingly
})
})
return Promise.all(childPromises)
})
})
// Now this is where we're reaching early
return Promise.all(catPromises)
}).then(() => {
// API call
})