loop through an array and check if array inside it has a certain value

user_9653879 0
Viewed 58

I have an array of objects like below

const arr = 
  [ { a: '', b: '', arr: [ { label: '2' }, { label: '3' }                 ] } 
  , { a: '', b: '', arr: [ { label: '1' }, { label: '2' }, { label: '3' } ] } 
  , { a: '', b: '', arr: [ { label: '1' }, { label: '3' }                 ] } 
  ]

I need to filter this array and get the objects in which the arr array has the label value of 2.

ie., expected result :

const arr = 
  [ { a: '', b: '', arr: [ { label: '2' }, { label: '3' }                 ] } 
  , { a: '', b: '', arr: [ { label: '1' }, { label: '2' }, { label: '3' } ] } 
  ]

I have tried something like this:

array.forEach((item) => item.arr.filter(i) => i.label === '2')

how would we get back a filtered array looping through this array which has label values as "2" inside the arr array?

How can I achieve the expected result?

filter foreach arrays javascript
3 Answers

With filter, some and destructuring

const arr = 
  [ { a: '', b: '', arr: [ { label: '2' }, { label: '3' }                 ] } 
  , { a: '', b: '', arr: [ { label: '1' }, { label: '2' }, { label: '3' } ] } 
  , { a: '', b: '', arr: [ { label: '1' }, { label: '3' }                 ] } 
  ]
  
const output = arr.filter(({ arr }) => arr.some(({ label }) => label === '2'));
  
console.log(output)

user_78994770

Like this:

let oldArray = array = [
   {
      "a":"",
      "b":"",
      "arr":[
         {
            "label":"2"
         },
         {
            "label":"3"
         }
      ]
   },
{
      "a":"",
      "b":"",
      "arr":[
         {
            "label":"1"
         },
         {
            "label":"2"
         },
         {
            "label":"3"
         }
      ]
   },
{
      "a":"",
      "b":"",
      "arr":[
         {
            "label":"1"
         },
         {
            "label":"3"
         }
      ]
   }
]

let newArray = oldArray.filter(item=>
  item.arr && item.arr.filter(inner=> inner.label == "2").length >= 1
)

console.log(newArray)

user_166347380

You can simply achieve this by using Array.filter() method along with Array.some()

Live Demo :

const arr = [
  { a: '', b: '', arr: [ { label: '2' }, { label: '3' }] },
  { a: '', b: '', arr: [ { label: '1' }, { label: '2' }, { label: '3' } ] },
  { a: '', b: '', arr: [ { label: '1' }, { label: '3' }] } 
];

const filteredArr = arr.filter(({ arr }) => arr.some(o => o.label === '2'));

console.log(filteredArr);

user_41163000
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