In Javascript, set the index variable of the respected duplicate value to true in the array

Question

In Javascript, set the index variable of the respected duplicate value to true in the array

I am seeking a solution for identifying duplicate values within an array of objects.

My goal is to set the value of a specific index variable to true if that index contains a duplicate value.

For example, consider the following array of objects:

let arr = [
        {
            name: 'abc',
            age: 20,
        },
    
        {
            name: 'xyz',
            age: 25,
        },
    
        {
            name: 'pqr',
            age: 22,
        },
    
        {
            name: 'abc',
            age: 27,
        },
    
        {
            name: 'abc',
            age: 26,
        },
    ]

In this case, indexes 3 and 4 have names that are duplicates of index 0. I would like to set the isError variable to true for indexes 3 and 4, and to false for the other indexes.

Any assistance on how to achieve this would be greatly appreciated.

Thank you.

javascript arrays object

Answer 1

Answer №1

Utilize a Set to keep track of existing names and then map through the array. Check if the name already exists in the Set, set the isError variable accordingly. Add the current name to the Set. Create a new object with the original data along with the isError property:

const checkForDuplicates = arr => {
  const storedNames = new Set();
  
  return arr.map(obj => {
    const isError = storedNames.has(obj.name)
    
    storedNames.add(obj.name)
    
    return { ...obj, isError };
  })
}

const sampleArray = [{"name":"abc","age":20},{"name":"xyz","age":25},{"name":"pqr","age":22},{"name":"abc","age":27},{"name":"abc","age":26}]

const result = checkForDuplicates(sampleArray)

console.log(result)

Answer 2

Utilize a Set to keep track of existing names and then map through the array. Check if the name already exists in the Set, set the isError variable accordingly. Add the current name to the Set. Create a new object with the original data along with the isError property:

const checkForDuplicates = arr => {
  const storedNames = new Set();
  
  return arr.map(obj => {
    const isError = storedNames.has(obj.name)
    
    storedNames.add(obj.name)
    
    return { ...obj, isError };
  })
}

const sampleArray = [{"name":"abc","age":20},{"name":"xyz","age":25},{"name":"pqr","age":22},{"name":"abc","age":27},{"name":"abc","age":26}]

const result = checkForDuplicates(sampleArray)

console.log(result)

Answer 3

Answer №2

To start, organize the array and then apply the map function. Once the objects are sorted by name in ascending order, use the map function to create a new array. During this process, check if the current object's name matches the previous one. If it does, add a duplicate key and assign a value to it.

 if (index !== 0 && item.name == k[index - 1].name) {

This line skips checking the first object in the sorted array as there is no previous object to compare with. It evaluates if the name of the current object matches the name of the previous object using item.name == k[index - 1].name.

let arr = [{
    name: 'abc',
    age: 20,
  },

  {
    name: 'xyz',
    age: 25,
  },

  {
    name: 'pqr',
    age: 22,
  },

  {
    name: 'abc',
    age: 27,
  },

  {
    name: 'abc',
    age: 26,
  },
];
let k = arr.sort(function(a, b) {
  return a.name.localeCompare(b.name);
});
let z = k.map(function(item, index) {
  if (index !== 0 && item.name == k[index - 1].name) {
    return {
      name: item.name,
      age: item.age,
      duplicate: true
    }
  } else {
    return {
      name: item.name,
      age: item.age
    }
  }
});
console.log(z)

Answer 4

To start, organize the array and then apply the map function. Once the objects are sorted by name in ascending order, use the map function to create a new array. During this process, check if the current object's name matches the previous one. If it does, add a duplicate key and assign a value to it.

 if (index !== 0 && item.name == k[index - 1].name) {

This line skips checking the first object in the sorted array as there is no previous object to compare with. It evaluates if the name of the current object matches the name of the previous object using item.name == k[index - 1].name.

let arr = [{
    name: 'abc',
    age: 20,
  },

  {
    name: 'xyz',
    age: 25,
  },

  {
    name: 'pqr',
    age: 22,
  },

  {
    name: 'abc',
    age: 27,
  },

  {
    name: 'abc',
    age: 26,
  },
];
let k = arr.sort(function(a, b) {
  return a.name.localeCompare(b.name);
});
let z = k.map(function(item, index) {
  if (index !== 0 && item.name == k[index - 1].name) {
    return {
      name: item.name,
      age: item.age,
      duplicate: true
    }
  } else {
    return {
      name: item.name,
      age: item.age
    }
  }
});
console.log(z)

Answer 5

Answer №3

To track and manage data, consider using an object as a tracker by assigning a key using the name.

Iterate through the data, checking if the name already exists as a key in the op object. If it does, change the isError property of the current element to true. Otherwise, create a new key in op and set the isError of the current element to false.

let arr = [{name :'abc',age : 20,},{name :'xyz',age : 25,},{name :'pqr',age : 22,},{name :'abc',age : 27,},{name :'abc',age : 26,},]

let op = {}

arr.forEach( (inp,index) => {
  if( op[inp.name] ){
    inp.isError = true
  } else{
    inp.isError = false
    op[inp.name] = inp
  }
})

console.log(arr)

Answer 6

To track and manage data, consider using an object as a tracker by assigning a key using the name.

Iterate through the data, checking if the name already exists as a key in the op object. If it does, change the isError property of the current element to true. Otherwise, create a new key in op and set the isError of the current element to false.

let arr = [{name :'abc',age : 20,},{name :'xyz',age : 25,},{name :'pqr',age : 22,},{name :'abc',age : 27,},{name :'abc',age : 26,},]

let op = {}

arr.forEach( (inp,index) => {
  if( op[inp.name] ){
    inp.isError = true
  } else{
    inp.isError = false
    op[inp.name] = inp
  }
})

console.log(arr)

In Javascript, set the index variable of the respected duplicate value to true in the array

Answer №1

Answer №2

Answer №3

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