减少返回空数组

Question

activeUsers - 猫鼬对象数组 activeUsers.campaings - 猫鼬对象数组 LandingsFromBinom - 存储 id [{id: 123, name: name}, {id: 133, name: name2}] 的对象数组

对于每个用户，我都有活动数组（mongoose doc），对于每个活动，我都有 langings 数组（mongoose doc）。

我从 db 中获取所有用户并开始为每个用户进行迭代。 对于每个广告系列，我都会获取“着陆”并开始为每个广告系列进行迭代。

查看 db 并比较我需要更改的 id 并将其值存储在“landingsIds”中

问题：当我控制台日志“数据”返回我空数组，但如果我 console.log 函数返回填充数组。如何解决？

 // Fetch users from db
  let activeUsers = await User.find().populate({
    path: 'campaigns',
    match: { active: true },
  })

  const data = activeUsers.reduce((results, user) => {
    // For each campaign get landings
    user.campaigns.forEach(async (campaign) => {
      const { landings } = await campaign.populate({
        path: 'landings',
        match: { active: true },
      })

      // Get only good ID
      const landingsIds = landings.reduce((results, landing) => {
        landingsFromBinom.forEach((binomLanding) => {
          if (
            parseInt(binomLanding.id) === landing.id &&
            binomLanding.inject >= landing.todayVisitors
          ) {
            results.push(landing.id)
          }
        })
        return results
      }, [])

      results.push({
        landings: landingsIds,
        user: user._id
      })
      // RETURN Filled array
      console.log(results)
    })
    return results
  }, [])

  // Return empty array
  console.log(data)

输出：

[]
[
  {
    landings: [ 3, 11, 1, 7 ],
    user: new ObjectId("617fb23b1e7ea187ae07a6ee")
  }
]

Answer 1

在 array.reduce 中使用 await 和 Promise.resolve

let activeUsers = await User.find().populate({
    path: 'campaigns',
    match: { active: true },
  })

  const data = await activeUsers.reduce(async (results, user) => {
    // For each campaign get landings
    user.campaigns.forEach(async (campaign) => {
      const { landings } = await campaign.populate({
        path: 'landings',
        match: { active: true },
      })

      // Get only good ID
      const landingsIds = landings.reduce((results, landing) => {
        landingsFromBinom.forEach((binomLanding) => {
          if (
            parseInt(binomLanding.id) === landing.id &&
            binomLanding.inject >= landing.todayVisitors
          ) {
            results.push(landing.id)
          }
        })
        return results
      }, [])

      results.push({
        landings: landingsIds,
        user: user._id
      })
      // RETURN Filled array
      console.log(results)
    })
   
  }, [], Promise.resolve(results))

  console.log(data)