Javascript - Create unique array list which has immediate same property values

TInamdar
November 11, 2023
179 views
3 votes
3 Answers

I have below array with objects which includes duplicates type values. I need unique array of objects based on immediate same type values.

Note:
If any object has immediate next same type values then it will make one unique array list. Else it will include another unique object list with same type value.

Array :

[ 
  { "object": 1, "start": "2018-07-08", "end": "2018-12-31", "type": "A", "user": "ABCD" }, 
  { "object": 2, "start": "2018-12-31", "end": "2019-06-26", "type": "A", "user": "ABCD" }, 
  { "object": 3, "start": "2019-06-26", "end": "2019-12-31", "type": "B", "user": "PQRS" }, 
  { "object": 4, "start": "2019-12-31", "end": "2020-06-31", "type": "B", "user": "PQRS" }, 
  { "object": 5, "start": "2021-12-31", "end": "2022-12-31", "type": "A", "user": "ABCD" }, 
  { "object": 6, "start": "2012-12-31", "end": "2022-06-26", "type": "A", "user": "ABCD" }, 
  { "object": 7, "start": "2022-06-26", "end": "2022-12-31", "type": "A", "user": "ABCD" }, 
  { "object": 8, "start": "2022-12-31", "end": "2023-06-26", "type": "A", "user": "ABCD" } 
]

In above array object 2 is immediate after object 1 with same type A value therefore it make one unique list with A. And after that objects 3,4,5 has immediate basis on type B value therefore it created another unique list. After object 2, object 3 there is no similar "type" value so first unique list end there. But again object 5,6,7,8 has immediate basis type A value therefore it created another unique list.

I expected below Output (if any object has one after another same value then it will create unique list else it will end there and make another separate objects list) :

[
   {
      "A":[
         {
            "object":1,
            "start":"2018-07-08",
            "end":"2018-12-31",
            "type":"A",
            "user":"ABCD"
         },
         {
            "object":2,
            "start":"2018-12-31",
            "end":"2019-06-26",
            "type":"A",
            "user":"ABCD"
         }
      ]
   },
   {
      "B":[
         {
            "object":3,
            "start":"2019-06-26",
            "end":"2019-12-31",
            "type":"B",
            "user":"PQRS"
         },
         {
            "object":4,
            "start":"2019-12-31",
            "end":"2020-06-31",
            "type":"B",
            "user":"PQRS"
         }
      ]
   },
   {
      "A":[
         {
            "object":5,
            "start":"2021-12-31",
            "end":"2022-12-31",
            "type":"A",
            "user":"ABCD"
         },
         {
            "object":6,
            "start":"2012-12-31",
            "end":"2022-06-26",
            "type":"A",
            "user":"ABCD"
         },
         {
            "object":7,
            "start":"2022-06-26",
            "end":"2022-12-31",
            "type":"A",
            "user":"ABCD"
         },
         {
            "object":8,
            "start":"2022-12-31",
            "end":"2023-06-26",
            "type":"A",
            "user":"ABCD"
         }
      ]
   }
]

Tags: grouping javascript

Answers

What you want is something like lodashs uniqBy, see documentation here https://lodash.com/docs/4.17.15#uniqBy

var input = [ { "object": 1, "start": "2018-07-08", "end": "2018-12-31", "type": "A", "user": "ABCD" }, { "object": 2, "start": "2018-12-31", "end": "2019-06-26", "type": "A", "user": "ABCD" }, { "object": 3, "start": "2019-06-26", "end": "2019-12-31", "type": "B", "user": "PQRS" }, { "object": 4, "start": "2019-12-31", "end": "2020-06-31", "type": "B", "user": "PQRS" }, { "object": 5, "start": "2021-12-31", "end": "2022-12-31", "type": "A", "user": "ABCD" }, { "object": 6, "start": "2012-12-31", "end": "2022-06-26", "type": "A", "user": "ABCD" }, { "object": 7, "start": "2022-06-26", "end": "2022-12-31", "type": "A", "user": "ABCD" }, { "object": 8, "start": "2022-12-31", "end": "2023-06-26", "type": "A", "user": "ABCD" } ]

var output = _.uniqBy(input, 'type')

// OR

var output = _.uniqBy(input, x => x.type)

// results in 
[
   {
      "object": 1,
      "start": "2018-07-08",
      "end": "2018-12-31",
      "type": "A",
      "user": "ABCD"
   },
   {
      "object": 3,
      "start": "2019-06-26",
      "end": "2019-12-31",
      "type": "B",
      "user": "PQRS"
   }
]

Try if it works for you.

function createUniqueLists(inputArray) {
  const result = [];
  let currentList = [];

  for (let i = 0; i < inputArray.length; i++) {
    const currentObject = inputArray[i];
    const currentType = currentObject.type;

    if (i === 0 || currentType !== inputArray[i - 1].type) {
      // Start a new unique list for a different type
      if (currentList.length > 0) {
        result.push({ [currentList[0].type]: currentList });
        currentList = [];
      }
    }

    currentList.push(currentObject);

    // If the next object has a different type, create a new unique list
    if (i < inputArray.length - 1 && currentType !== inputArray[i + 1].type) {
      result.push({ [currentType]: currentList });
      currentList = [];
    }
  }

  return result;
}

const inputArray = [
  { "object": 1, "start": "2018-07-08", "end": "2018-12-31", "type": "A", "user": "ABCD" },
  { "object": 2, "start": "2018-12-31", "end": "2019-06-26", "type": "A", "user": "ABCD" },
  { "object": 3, "start": "2019-06-26", "end": "2019-12-31", "type": "B", "user": "PQRS" },
  { "object": 4, "start": "2019-12-31", "end": "2020-06-31", "type": "B", "user": "PQRS" },
  { "object": 5, "start": "2021-12-31", "end": "2022-12-31", "type": "A", "user": "ABCD" },
  { "object": 6, "start": "2012-12-31", "end": "2022-06-26", "type": "A", "user": "ABCD" },
  { "object": 7, "start": "2022-06-26", "end": "2022-12-31", "type": "A", "user": "ABCD" },
  { "object": 8, "start": "2022-12-31", "end": "2023-06-26", "type": "A", "user": "ABCD" }
];

const output = createUniqueLists(inputArray);
console.log(JSON.stringify(output, null, 2));

You could take a closure over type anf check the type from each element. If same, add to the last element of the result set, if not, create a new object. Update type.

const
    data = [{ object: 1, start: "2018-07-08", end: "2018-12-31", type: "A", user: "ABCD" }, { object: 2, start: "2018-12-31", end: "2019-06-26", type: "A", user: "ABCD" }, { object: 3, start: "2019-06-26", end: "2019-12-31", type: "B", user: "PQRS" }, { object: 4, start: "2019-12-31", end: "2020-06-31", type: "B", user: "PQRS" }, { object: 5, start: "2021-12-31", end: "2022-12-31", type: "A", user: "ABCD" }, { object: 6, start: "2012-12-31", end: "2022-06-26", type: "A", user: "ABCD" }, { object: 7, start: "2022-06-26", end: "2022-12-31", type: "A", user: "ABCD" }, { object: 8, start: "2022-12-31", end: "2023-06-26", type: "A", user: "ABCD" }],
    result = data.reduce((type => (r, o) => {
        if (type === o.type) {
            r.at(-1)[type].push(o);
        } else {
            type = o.type;
            r.push({ [type]: [o] });
        }
        return r;
    })(), []);

console.log(result);

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Javascript – Create unique array list which has immediate same property values

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