promise链未按顺序执行

Question

我遇到一个奇怪的问题，我调用"createProductLine"；在以下代码中：

module.exports.postProductLine = (req, res) => {
DAL.createProductLine(req.body.category, req.body.type, req.body.name, req.body.description, req.body.tags)
.then(() => {
res.sendStatus(200)
console.log("SUCCESS")
})
.catch(err => {
res.status(500).send(err.message)
console.error(err)
})
}

这里是"；createProductLine"；功能：

module.exports.createProductLine = async (category, type, name, description, tags) => {
const [pool, dbErr] = await tryCatch(await database.pool)
if(dbErr) return Promise.reject()
const [connection, connectErr] = await tryCatch(pool.getConnection())
if(connectErr) return Promise.reject()
connection.beginTransaction()
.then(() => {
const query = `INSERT INTO product_lines (category,type,name,description,last_update,creation_date) VALUES (?,?,?,?,NOW(),NOW())`
return connection.query(query, [category, type, name, description])
})
.then(({insertId: productLineId} = {}) => Promise.all([
Promise.resolve(productLineId),
...tags.map(productLineTag => new Promise(async (resolve, reject) => {
let query = "SELECT id FROM tags WHERE name=?"
const [existingTag, err1] = await tryCatch(connection.query(query, [productLineTag]))
if(err1) return reject(`could not get tag (${productLineTag}) id`)
if(existingTag.length === 0) {
query = "INSERT INTO tags (name) VALUES (?)"
const [{insertId}, err2] = await tryCatch(connection.query(query, [productLineTag]))
if(err2) return reject(`could not insert tag (${productLineTag})`)
return resolve(insertId)
}
return resolve(existingTag[0].id)
}))
]))
// CHANGE OF ORDER HAPPENS HERE
.then(ids => Promise.all(
ids.reduce((acc, cur, i, arr) => {
if(i === 0) return acc
acc[i - 1] = connection.query(
`INSERT INTO product_lines_tags (product_line_id, tag_id) VALUES (${arr[0]}, ${cur})`
)
return acc
}, new Array(ids.length - 1))
))
.then(async () => {
console.log("THEN")
await connection.commit()
return connection.release()
})
.catch(async err => {
console.log("CATCH", err)
await connection.rollback()
await connection.release()
return err
})
}

由于某种原因，所有.then的执行顺序并没有按预期进行，在完成第二个之后(在"createProductLine"内部(，它在第一个代码块(postProductLine函数(中执行.then，然后返回执行其余部分。

我不明白它为什么会这样，有人知道如何解决这个问题吗？

Answer 1

module.exports.createProductLine = async (category, type, name, description, tags) => {
const pool = await database.pool
const connection = await pool.getConnection()
await connection.beginTransaction()
try {
const {insertId: productLineId} = await connection.query(
"INSERT INTO product_lines (category,type,name,description) VALUES (?,?,?,?)", 
[category, type, name, description]
)
const tagIds = await Promise.all(tags.map(async tag => {
const existingTag = await connection.query(
"SELECT id FROM tags WHERE name=?", [tag]
)
if(existingTag.length === 0) { 
const {insertId} = await connection.query(
"INSERT INTO tags (name) VALUES (?)", [tag]
)
return insertId
}
return existingTag[0].id
}))
await Promise.all(tagIds.map(tagId => connection.query(
`INSERT INTO product_lines_tags (product_line_id, tag_id) VALUES (${productLineId}, ${tagId})`
)))
await connection.commit()
await connection.release()
return true
}
catch(err) {
await connection.rollback()
await connection.release()
return Promise.reject(err)
}
}