Reduce return empty array

Question

activeUsers - array of mongoose objects activeUsers.campaings - array of mongoose objects landingsFromBinom - array of objects where store id [{id: 123, name: name}, {id: 133, name: name2}]

For each user i have campaigns array (mongoose doc), for each campaigns i have langings array (mongoose doc).

I fetch all users from db and start iterate for each. For each campaign i fetch 'landings' and start iterate for each.

Look at db and compare id's that i need to change and store it value in "landingsIds"

PROBLEM: when i console log "data" that returns me empty array, but if i console.log in function that return filled array. How to fix it?

 // 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)

Output :

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

mohammad Naimi · Accepted Answer · 2021-11-05 11:02:24Z

1

use await in array.reduce with 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)

edited Nov 5, 2021 at 11:02

answered Nov 5, 2021 at 9:09

mohammad Naimi

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2 Comments

sky sky Over a year ago

returned undefined

mohammad Naimi Over a year ago

Try again i update my answer

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