I am trying to filter unique object from the places Array inside the list Array, but not able to get the exact solution to find the unique place name, please find the array data below=>

"list":[
   {
      "id":1,
      "uID": 1 
      "places":[
         {
            "name":"USA"
         },
         {
            "name":"USA"
         },
         {
            "name":"GER"
         }
      ]
   },
   {
      "id":2,
      "uID":2
      "places":[
         {
            "name":"USA"
         },
         {
            "name":"GER"
         },
         {
            "name":"GER"
         }
      ]
   }
]

The Expected output should be like this =>

"list":[
   {
      "id":1,
      "uID": 1 
      "places":[
         {
            "name":"USA"
         },
         {
            "name":"GER"
         }
      ]
   },
   {
      "id":2,
      "uID":2
      "places":[
         {
            "name":"USA"
         },
         {
            "name":"GER"
         }
      ]
   }
]

Appreciate your help.

CodePudding user response：

You can use Array.map() to map to map each member of the list to a new value.

For each value, we can remove duplicate places using a Set object.

We create our list of unique places, then assign to the places property of each output item.

const list = [ { "id":1, "uID": 1, "places":[ { "name":"USA" }, { "name":"USA" }, { "name":"GER" } ] }, { "id":2, "uID":2, "places":[ { "name":"USA" }, { "name":"GER" }, { "name":"GER" } ] } ]

const result = list.map(({ places, ...obj }) => {
    const uniquePlaces = new Set(places.map(item => item.name));
    return { ...obj, places: [ ...uniquePlaces].map(name => ({ name })) }
})

console.log('Result:', result);

.as-console-wrapper { max-height: 100% !important; }

CodePudding user response：

You can use Set() to filter duplicate by using add() method. for more reference take a look at this link : https://levelup.gitconnected.com/how-to-find-unique-values-by-property-in-an-array-of-objects-in-javascript-50ca23db8ccc

CodePudding user response：

1. Convert the object(s) in places array as (JSON) string via JSON.stringify().
2. With new Set() to distinct the JSON string.
3. Convert to array from result 2 via Array.from().
4. Convert each (JSON) string in the array (from 3) to the object via JSON.parse().

list = list.map(x => {
    x.places = Array.from([...new Set(x.places.map(x => JSON.stringify(x)))])
        .map(x => JSON.parse(x));

    return x;
})

Sample Typescript Playground

CodePudding user response：

const foo = {
"list":[
   {
      "id":1,
      "uID": 1,
      "places":[
         {
            "name":"USA"
         },
         {
            "name":"USA"
         },
         {
            "name":"GER"
         }
      ]
   },
   {
      "id":2,
      "uID":2,
      "places":[
         {
            "name":"USA"
         },
         {
            "name":"GER"
         },
         {
            "name":"GER"
         }
      ]
   }
]};

const newList = foo.list.map(element => {
  let filteredPlaces = [];
  element.places.forEach(place => {
    const checkExistingPlaces = filteredPlaces.some(elem => elem.name === place.name);
    if (!checkExistingPlaces) {
      filteredPlaces.push(place);
    }
  });
  element.places = filteredPlaces;
  return element;
});

console.log(newList)