Javascript Question posted in
A very good W3school tutorial can be found here.

Javascript – Extract values from arrays in

I have a response object that I’m wanting to extract all of the id values out, but I’m not sure the best way to go about it…

const obj = {
  "responseArray":[
    {
      "accounts":[
        {
          "products":[
            {
              "id":"123",
            }
          ]
        },
        {
          "products":[
            {
              "id":"456",
            }
          ]
        }
      ]
    },
    {
      "accounts":[
        {
          "products":[
            {
              "id":"987",
            }
          ]
        },
        {
          "products":[
            {
              "id":"654",
            }
          ]
        }
      ]
    }
  ]
}

The closest I’ve gotten is with mapping

const mapped = obj.responseArray.map(item => item?.accounts.map(acc => acc.products.map(prod => prod.id)))

// Response
// [ [ [Array], [Array] ], [ [Array], [Array] ] ]

These Array bits do actually contain the IDs I’m after, it’s just obviously not in the format I’d like…

Tags:

4

Answers


  1. 0

    You can use flatMap to get a simple array instead of an array of arrays :

    const obj = {
  "responseArray":[
    {
      "accounts":[
        {
          "products":[
            {
              "id":"123",
            }
          ]
        },
        {
          "products":[
            {
              "id":"456",
            }
          ]
        }
      ]
    },
    {
      "accounts":[
        {
          "products":[
            {
              "id":"987",
            }
          ]
        },
        {
          "products":[
            {
              "id":"654",
            }
          ]
        }
      ]
    }
  ]
}

const mapped = obj.responseArray.flatMap(item => item?.accounts.flatMap(acc => acc.products.map(prod => prod.id)))

console.log(mapped)
    Login or Signup to reply.
  2. 0

    With "modern" (Chrome 69, Firefox 62, Edge 79, Opera 56, Safari 12) versions of JavaScript you can Array.prototype.flatMap:

    obj.responseArray
  .flatMap(x => x.accounts)
  .flatMap(x => x.products)
  .map(x => x.id)
// [ '123', '456', '987', '654' ]

    flatMap takes a function that returns an array and will map all arrays of this function into one big array, which can then be further processed.

    Login or Signup to reply.
  3. 0

    I am using the forEach to get the job done.

    const obj = {
  "responseArray": [{
      "accounts": [{
          "products": [{
            "id": "123",
          }]
        },
        {
          "products": [{
            "id": "456",
          }]
        }
      ]
    },
    {
      "accounts": [{
          "products": [{
            "id": "987",
          }]
        },
        {
          "products": [{
            "id": "654",
          }]
        }
      ]
    }
  ]
}
let result=[];
obj.responseArray.forEach(o=>{
    o.accounts.forEach(account=>{
    account.products.forEach(product=>{
        result.push(product.id);
    })
  })
})
console.log(result)
    Login or Signup to reply.
  4. 0

    I guess what you are looking for is something like this,
    We need to use flatMap to flatten and map over the arrays:

    obj.responseArray
    .flatMap(item => item.accounts)
    .flatMap(account => account.products)
    .map(product => product.id);

// response: [ '123', '456', '987', '654' ]
    Login or Signup to reply.
Please signup or login to give your own answer.

Back To Top
Search