Show Only Single Item If Same in React/ES6

Question

I wanted to show only a single item if it has the same it has same contact_id and id.

Expected output is Name: Robert Williams, Name: John Jones

RESPONSE

{
  "id": "8888",
  "contact_id": "3424",
  "contact_name": "Robert Williams",
},
{
  "id": "9999",
  "contact_id": "4343",
  "contact_name": "John Jones",
},
{
  "id": "8888",
  "contact_id": "3424",
  "contact_name": "Robert Williams",
}

CODE

{
  data.map((item, index) => {
    return (
      <div key={index}>
        <h1>Name</h1>
        <p>
          {item.contact_name}
        </p>
      </div>
    );
  });
}

https://stackoverflow.com/questions/31740155/lodash-remove-duplicates-from-array , does this solve your question? — timbersaw, Mar 03 '21 at 17:16

score 2 · Answer 1 · answered Mar 03 '21 at 17:31

One liner ES6 can do the magic:

const arr = [{
  "id": "8888",
  "contact_id": "3424",
  "contact_name": "Robert Williams",
},
{
  "id": "9999",
  "contact_id": "4343",
  "contact_name": "John Jones",
},
{
  "id": "8888",
  "contact_id": "3424",
  "contact_name": "Robert Williams",
}]

   const data = arr.filter((v,i,a)=>a.findIndex(t=>(t.id === v.id && t.contact_id===v.contact_id))===i)

and then

{
  data.map((item, index) => {
    return (
      <div key={index}>
        <h1>Name</h1>
        <p>
          {item.contact_name}
        </p>
      </div>
    );
  });
}

Giorgi Moniava · Answer 2 · 2021-03-03T17:34:50.670

Something like this?

let data = [{
        "id": "8888",
        "contact_id": "3424",
        "contact_name": "Robert Williams",
    },
    {
        "id": "9999",
        "contact_id": "4343",
        "contact_name": "John Jones",
    },
    {
        "id": "8888",
        "contact_id": "3424",
        "contact_name": "Robert Williams",
    }
];

let transform = (data) => {

    let existing = {};
    let result = [];

    data.forEach(x => {

        if (!existing[x.id] || !existing[x.id][x.contact_id]) {
            existing[x.id] = {
                [x.contact_id]: true
            };
            result.push(x);


        }

    });

    return result;

}

console.log(transform(data));

Now you can render result returned by above function.

score 1 · Accepted Answer · answered Mar 03 '21 at 18:24

You can use Array.prototype.reduce():

  const dataTransformed = data.reduce((arr, curr) => {
    return arr.find(
      item => item.id === curr.id && item.contact_id === curr.contact_id
    )
      ? [...arr]
      : [...arr, curr];
  }, []);

Then iterate over the transformed array

score 0 · Answer 4 · answered Mar 03 '21 at 17:56

Create an object and a filter function:

const memo = {};

const filter = (item) => {
  if(!memo[item.id]){
     return true;
  }else {
    memo[item.id] = item.id;
    return false;
  }
}

Then in your render:

{
  data.filter(filter).map((item, index) => {
      return (
         <div key={index}>
           <h1>Name</h1>
           <p>
             {item.contact_name}
           </p>
         </div>); 
  });
}

score -1 · Answer 5 · answered Mar 03 '21 at 17:28

Here is a solution:

 {
  data.map((item, index) => {
    if(item.contact_name === item.contact_id) {
       return (
          <div key={index}>
           <h1>Name</h1>
          <p>
            {item.contact_name}
          </p>
        </div>
      );

    }  else {
        return null;
 }
    
  });
}

Show Only Single Item If Same in React/ES6

5 Answers5