javascript check if array contains more than one element with exact same property

Question

I have an array of objects:
[
  {
   id: 1,
   sku: 'aaaa'
  },
  {
   id: 2,
   sku: 'bbbb'
  },
  {
   id: 3,
   sku: 'cccc'
  },
  {
   id: 4,
   sku: 'aaaa'
  }
]

How can I check that there are more than one element with the same sku property existing in the array?
For example: I have to elements with the same prop sku ('aaaa') - and in this case I need to do something in other case - nothing

micronyks · Answer

const a = [
  {
   id: 1,
   sku: "aaaa"
  },
  {
   id: 2,
   sku: "bbbb"
  },
  {
   id: 3,
   sku: "cccc"
  },
  {
   id: 4,
   sku: "aaaa"
  }
];

a.reduce((acc, obj)=>{

// looping through each sku & adding them in acc
    acc.push(obj.sku);
    
    // check if current sku already exits in acc.
    const duplicate = acc.filter(x=>x === obj.sku);
    
    if(duplicate.length>1){
          // do something or nothing with current obj as similar SKUs are found
          // i'm adding a new property called x=10 if same SKUs are found.
          obj.x = 10;
    }else{
          // do something or nothing with current obj as similar SKUs are found
          // i'm adding a new property called y=10 if not same SKUs.
          obj.y=10;
 }
 
 return acc;

}, []);

console.log(a);

Anku · Answer

You can check like below array function 'some' will help you
 var arr = [
  {
   id: 1,
   sku: 'aaaa'
  },
  {
   id: 2,
   sku: 'bbbb'
  },
  {
   id: 3,
   sku: 'cccc'
  },
  {
   id: 4,
   sku: 'aaaa'
  }
]

const val = 'aaaa'

const isAvailable = arr.some(function(arrVal) {
        return val === arrVal.sku;
});

//here isAvailable will return true or false

Mahdy Aslamy · Answer

You can use example code like this:


var a = [
  {
   id: 1,
   sku: 'aaaa'
  },
  {
   id: 2,
   sku: 'bbbb'
  },
  {
   id: 3,
   sku: 'cccc'
  },
  {
   id: 4,
   sku: 'aaaa'
  }
];

var b = {};
a.forEach(el => {
  if (b[el.sku]) {
    b[el.sku].count++;
  } else {
    b[el.sku] = { id: el.id, count: 1 };
  }
});

console.log(b);

lastr2d2 · Answer

Use set to get an array holding unique skus and compare the length
var skus = items.map(v=>v.sku);
var uniqueSkus = new Set(skus);
console.log(skus.length === uniqueSkus.size)

javascript check if array contains more than one element with exact same property

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