How to find out if an object from an array is present also in another array

Hi,

I have 2 objects that contain arrays of objects within like this:

var array1 = {"id":"car", "name":"honda", "virtues":[{"price":99}, {"size" : ""}, {"condition" : "new"}]};

var array2 = {'userid' : '2', 'username' : 'john','prefs' : [{"price":1}]};

I dont care for size all I want is price and condition so I want to find out if those are present also in array2 so I did this:

calceffect = function(myarray) {
 myarray.map(x => {
  for(let key in x) {
   if(key!= 'size') {
    array2.prefs.map(d => 
     {
      for(let k in d) {
       if(k == key){
        console.log('present');
       } else {
        console.log('absent');
       }
      }
     }
    );
   }
  }
 });
}

calceffect(array1.virtues); //in this case it will output 'it is present' for "price" and 'absent' for "condition"

it works as expected, however I find it like a little too convoluted. Is there a cleaner way to get the same result?

Thank you.

You could get the keys, count and get the result

<!-- begin snippet: js hide: false console: true babel: false -->

<!-- language: lang-js -->

const
    getKeys = a => a.flatMap(o => Object.keys(o)),
    a = { id: "car", name: "honda", virtues: [{ price: 99 }, { size: "" }, { condition: "new" }] },
    b = { userid: '2', username: 'john', prefs: [{ price: 1 }] },
    add = (object, d) => v => object[v] = (object[v] || 0) + d,
    counts = {}
    result = { common: [], unique: [] };

getKeys(a.virtues).forEach(add(counts, 1));
getKeys(b.prefs).forEach(add(counts, -1));

Object.entries(counts).forEach(([k, v]) => result[v ? 'unique' : 'common'].push(k));

console.log(result);

<!-- end snippet -->

there is a way that you can use the built in JavaScript methods such as filter and some to check if the price and condition properties are in array2.prefs.

One way you could refactor this is making a function that returns a boolean:

let array1 = {"id":"car", "name":"honda", "virtues":[{"price":99}, {"size" : ""}, {"condition" : "new"}]};

let array2 = {'userid' : '2', 'username' : 'john','prefs' : [{"price":1}]};

First we filter out the objects in array1.virtues that have a price or condition, secondly we use the every method to check if all objects satisfy the condition that there exists at least one object in array.prefs that has both a price and a condition. some method is used to check for the existing object.

let priceAndCondition = array1.virtues.filter(x => x.price || x.condition).every(x => array2.prefs.some(y => y.price && y.condition));

console.log(priceAndCondition);

You can achieve it by using below code -

// create an array of the desired keys to check
const desiredKeys = ['price', 'condition'];

// check if each desired key is present in array2 prefs
const presentKeys = desiredKeys.filter(key => array2.prefs.some(pref => 
pref.hasOwnProperty(key)));

// output the result
presentKeys.forEach(key => console.log(`${key} is present`));

If you want to use array of undesired keys, then you can use below code -

// create an array of the desired keys to check
const unDesiredKeys = ['size'];

// check if each desired key is present in array2 prefs
const presentKeys = unDesiredKeys.filter(key => 
      array2.prefs.some(pref => !pref.hasOwnProperty(key)));

// output the result
presentKeys.forEach(key => console.log(`${key} is present`));

this is good?

var array1 = {
    "id":"car",
    "name":"honda",
    "virtues":[{"price":99}, {"size" : ""}, {"condition" : "new"}]
};

var array2 = {
    'userid' : '2',
    'username' : 'john',
    'prefs' : [{"price":1}]
};

const value1 = Object.values(array1);
const value2 = Object.values(array2);
const vObj1 = value1.filter(item => typeof item === "object");
const vObj2 = value2.filter(item => typeof item === "object");
const obj1 = vObj1[0];
const obj2 = vObj2[0];

for(let index of obj1){
    for(let index2 of obj2){
    console.log(Object.keys(index2).filter(test => test ===  Object.keys(index)[0]));
    }
}