Iterate through a collection of nested objects and check them against an object contained within an array

Question

Iterate through a collection of nested objects and check them against an object contained within an array

I'm facing a frustrating issue in Firebase where I am required to compare an object returned to me with an array.

I need assistance in completing this method:

const removeAlreadySeenUsersFromQueue = (newUsers, likedUsers) => {

}

The scenario is that newUsers is an array of objects, each containing an id of interest.

On the other hand, likedUsers is returning as an array of objects within objects, like so:

[{object1: {}, object2: {}, object3: {}]

, essentially an array of length one. Within each object, there exists an id key that I need to identify. My goal is to compare both arrays and return an array solely containing objects whose ids appear only in newUsers and not in likedUsers. I believe object.keys() might be useful here, but my current attempts are unsuccessful

For example:

[{id: 4444}, {id: 5555}, {id: 6666}]

[{object1: {id: 4444}, object2: {id: 5555}, object3: {id: 121241}}]

After comparing these two arrays, I expect to receive just {id: 6666}.

javascript arrays object key

Answer 1

Answer №1

This code snippet is designed to handle multiple matches by filtering out elements from one array that match certain criteria in another array. For demonstration purposes, an additional object with the id value of 7777 has been added to the first input array.

// Input arrays
var array1 = [{id: 4444}, {id: 5555}, {id: 6666}, {id: 7777}];
var array2 = [{object1: {id: 4444}, object2: {id: 5555}, object3: {id: 121241}}];

// Output array after filtering
var newArray = array1.filter(function(obj) {
    // Assume the element from array1 should be added by default
    var includeElement = true;

    // Check if the element from array1 exists in array2 and update includeElement accordingly
    Object.keys(array2[0]).forEach(function(key) { 
        if (array2[0][key].id == obj.id)     
            includeElement = false; 
    });

    // Complete the filter function by returning whether to include the element or not
    return includeElement;
});

// Log the filtered output array
console.log(newArray);

Answer 2

This code snippet is designed to handle multiple matches by filtering out elements from one array that match certain criteria in another array. For demonstration purposes, an additional object with the id value of 7777 has been added to the first input array.

// Input arrays
var array1 = [{id: 4444}, {id: 5555}, {id: 6666}, {id: 7777}];
var array2 = [{object1: {id: 4444}, object2: {id: 5555}, object3: {id: 121241}}];

// Output array after filtering
var newArray = array1.filter(function(obj) {
    // Assume the element from array1 should be added by default
    var includeElement = true;

    // Check if the element from array1 exists in array2 and update includeElement accordingly
    Object.keys(array2[0]).forEach(function(key) { 
        if (array2[0][key].id == obj.id)     
            includeElement = false; 
    });

    // Complete the filter function by returning whether to include the element or not
    return includeElement;
});

// Log the filtered output array
console.log(newArray);

Answer 3

Answer №2

To retrieve the ids, you can utilize the reduce method and then apply the filter function in combination with the some function.

The result of the reduce operation may contain duplicate elements like [666, 555, 666, 777], but this scenario is not considered since your example does not involve repeated ids.

var source = [{ id: 4444 }, { id: 5555 }, { id: 6666 }, { id: 123456 }];
var content = [{ object1: { id: 4444 }, object2: { id: 5555 }, object3: { id: 121241 }}];

var ids = content.reduce((acc, curr) => [...acc, ...Object.keys(curr).map((k) => curr[k].id)] , []);

var result = source.filter((e) => {
  return !ids.some((c) => {
    return e.id === c;
  });
});

console.log(result);

Resources

Answer 4

To retrieve the ids, you can utilize the reduce method and then apply the filter function in combination with the some function.

The result of the reduce operation may contain duplicate elements like [666, 555, 666, 777], but this scenario is not considered since your example does not involve repeated ids.

var source = [{ id: 4444 }, { id: 5555 }, { id: 6666 }, { id: 123456 }];
var content = [{ object1: { id: 4444 }, object2: { id: 5555 }, object3: { id: 121241 }}];

var ids = content.reduce((acc, curr) => [...acc, ...Object.keys(curr).map((k) => curr[k].id)] , []);

var result = source.filter((e) => {
  return !ids.some((c) => {
    return e.id === c;
  });
});

console.log(result);

Resources

Answer 5

Answer №3

Did you mention that your array has a length of 1? So, essentially, you're referring to something like [{}]? Why not consider changing it to [{}, {}, {}] and then looping through it using the for (element of array) - for of loop. Alternatively, if you prefer having all elements within one object, you can iterate over it using a for in loop by going with for (element in array[0]).

UPDATE Upon seeing your example, I've come up with this snippet:

const firstArray = [{id: 4444}, {id: 5555}, {id: 6666}];
const secondArray = [{object1: {id: 4444}, object2: {id: 55555}, object3: {id: 121241}}];

for (let object in secondArray[0]) {
   if (firstArray.some(el => el.id === secondArray[0][object].id)} {
      //perform some action
   }
}

Answer 6

Did you mention that your array has a length of 1? So, essentially, you're referring to something like [{}]? Why not consider changing it to [{}, {}, {}] and then looping through it using the for (element of array) - for of loop. Alternatively, if you prefer having all elements within one object, you can iterate over it using a for in loop by going with for (element in array[0]).

UPDATE Upon seeing your example, I've come up with this snippet:

const firstArray = [{id: 4444}, {id: 5555}, {id: 6666}];
const secondArray = [{object1: {id: 4444}, object2: {id: 55555}, object3: {id: 121241}}];

for (let object in secondArray[0]) {
   if (firstArray.some(el => el.id === secondArray[0][object].id)} {
      //perform some action
   }
}

Iterate through a collection of nested objects and check them against an object contained within an array

Answer №1

Answer №2

Resources

Answer №3

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