An array of objects in JavaScript is populated with identical data as the original array

Question

An array of objects in JavaScript is populated with identical data as the original array

I am attempting to gather all similar data values into an array of objects. Here is my initial input:

var a = [{
    name: "Foo",
    id: "123",
    data: ["65d4ze", "65h8914d"]
  },
  {
    name: "Bar",
    id: "321",
    data: ["65d4ze", "894ver81"]
  }
]

The desired result is:

["65d4ze"]

I have tried looping through the object to achieve this outcome, but I have become quite perplexed... I am unsure how to determine if the result exists in all data arrays.

var a = [{
        name: "Foo",
        id: "123",
        data: ["65d4ze", "65h8914d"]
      },
      {
        name: "Bar",
        id: "321",
        data: ["65d4ze", "894ver81"]
      }
    ],
  b = [],
  c = []
a.forEach(function(object) {
  b.push(object.data.map(function(val) {
    return val;
    })
  );
});

console.log(b);

javascript arrays

Answer 1

Answer №1

You have the option to utilize data mapping to extract the shared values using Array#map, Array#reduce, Array#filter, Set, and Set#has.

var array = [{ name: "Foo", id: "123", data: ["65d4ze", "65h8914d"] }, { name: "Bar", id: "321", data: ["65d4ze", "894ver81"] }],
    key = 'data',
    common = array
        .map(obj => obj[key])
        .reduce((arr1, arr2) => arr2.filter(Set.prototype.has, new Set(arr1)));

console.log(common);

Answer 2

You have the option to utilize data mapping to extract the shared values using Array#map, Array#reduce, Array#filter, Set, and Set#has.

var array = [{ name: "Foo", id: "123", data: ["65d4ze", "65h8914d"] }, { name: "Bar", id: "321", data: ["65d4ze", "894ver81"] }],
    key = 'data',
    common = array
        .map(obj => obj[key])
        .reduce((arr1, arr2) => arr2.filter(Set.prototype.has, new Set(arr1)));

console.log(common);

Answer 3

Answer №2

To filter the first array based on the presence of values in other arrays, utilize the Array#filter method along with the Array#every method.

let result = initialArray[0].data.filter(value => remainingArrays.every(array => array.data.includes(value)));

var initialArray = [{
    name: "Foo",
    id: "123",
    data: ["65d4ze", "65h8914d"]
  },
  {
    name: "Bar",
    id: "321",
    data: ["65d4ze", "894ver81"]
  }
];

let result = initialArray[0].data.filter(value => remainingArrays.every(array => array.data.includes(value)));

console.log(result)

Answer 4

To filter the first array based on the presence of values in other arrays, utilize the Array#filter method along with the Array#every method.

let result = initialArray[0].data.filter(value => remainingArrays.every(array => array.data.includes(value)));

var initialArray = [{
    name: "Foo",
    id: "123",
    data: ["65d4ze", "65h8914d"]
  },
  {
    name: "Bar",
    id: "321",
    data: ["65d4ze", "894ver81"]
  }
];

let result = initialArray[0].data.filter(value => remainingArrays.every(array => array.data.includes(value)));

console.log(result)

Answer 5

Answer №3

let array = [{
      name: "Foo",
      id: "123",
      data: ["65d4ze", "65h8914d"]
    },
       {
          name: "Bar",
          id: "321",
          data: ["65d4ze", "894ver81"]
    }
  ],
  object = {};
array.forEach(function(item) {
  item.data.forEach(function(dataItem) {
    if (!object.hasOwnProperty(dataItem)) {
      object[dataItem] = 0;
    }
    object[dataItem]++;
  });
});
resultArray = []
for (let key in object) {
  if (object.hasOwnProperty(key)) {
    if (object[key] > 1) {
      resultArray.push(key)
    }
  }
}
console.log(resultArray);

Answer 6

let array = [{
      name: "Foo",
      id: "123",
      data: ["65d4ze", "65h8914d"]
    },
       {
          name: "Bar",
          id: "321",
          data: ["65d4ze", "894ver81"]
    }
  ],
  object = {};
array.forEach(function(item) {
  item.data.forEach(function(dataItem) {
    if (!object.hasOwnProperty(dataItem)) {
      object[dataItem] = 0;
    }
    object[dataItem]++;
  });
});
resultArray = []
for (let key in object) {
  if (object.hasOwnProperty(key)) {
    if (object[key] > 1) {
      resultArray.push(key)
    }
  }
}
console.log(resultArray);

Answer 7

Answer №4

Utilize the flatten method within the array:

let x = [{
        name: "Alice",
        id: "456",
        data: ["65d4ze", "65h8914d"]
      },
      {
        name: "Bob",
        id: "654",
        data: ["65d4ze", "894ver81"]
      }
    ],
  y = [],
  z = []
x.forEach(function(obj) {
  y.push(obj.data.map(function(value) {
    return value;
    })
  );
});

console.log(y.flatten());

Answer 8

Utilize the flatten method within the array:

let x = [{
        name: "Alice",
        id: "456",
        data: ["65d4ze", "65h8914d"]
      },
      {
        name: "Bob",
        id: "654",
        data: ["65d4ze", "894ver81"]
      }
    ],
  y = [],
  z = []
x.forEach(function(obj) {
  y.push(obj.data.map(function(value) {
    return value;
    })
  );
});

console.log(y.flatten());

Answer 9

Answer №5

To find items with the same occurrence in all objects within an array, utilize the reduce and concat functions for each data array, analyzing the count of each item.

If all objects across the array contain the same item, it will be returned at the end of the process.

Keep in mind that this method is effective for extracting items with consistent occurrences throughout all objects in the array. Items with duplicates that do not meet this criteria will not be extracted.

let a = [{name: "Foo",id: "123",data: ["65d4ze", "65h8914d"]},{name: "Bar",id: "321",data: ["65d4ze", "894ver81"]}];

let arr = a.reduce((prev,next) => prev.data.concat(next.data));
let counts = {};
let result = [];
for (var i = 0; i < arr.length; i++) {
  var num = arr[i];
  counts[num] = counts[num] ? counts[num] + 1 : 1;
}

for (let i in counts) {
    if (counts[i] === a.length) {
        result.push(i);
    }
}
console.log(result);

Answer 10

To find items with the same occurrence in all objects within an array, utilize the reduce and concat functions for each data array, analyzing the count of each item.

If all objects across the array contain the same item, it will be returned at the end of the process.

Keep in mind that this method is effective for extracting items with consistent occurrences throughout all objects in the array. Items with duplicates that do not meet this criteria will not be extracted.

let a = [{name: "Foo",id: "123",data: ["65d4ze", "65h8914d"]},{name: "Bar",id: "321",data: ["65d4ze", "894ver81"]}];

let arr = a.reduce((prev,next) => prev.data.concat(next.data));
let counts = {};
let result = [];
for (var i = 0; i < arr.length; i++) {
  var num = arr[i];
  counts[num] = counts[num] ? counts[num] + 1 : 1;
}

for (let i in counts) {
    if (counts[i] === a.length) {
        result.push(i);
    }
}
console.log(result);

An array of objects in JavaScript is populated with identical data as the original array

Answer №1

Answer №2

Answer №3

Answer №4

Answer №5

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