How can we print value from an array if two array matches with some value in JavaScript?

user_15279967 0
Viewed 82

I have to compare two array of objects and check if the same item includes in the other array.

const array1 = [
    { item: "orange", id: 11 },
    { item: "apple", id: 12 },
];

const array2 = [10, 11, 12];

If I am checking with a value from array2 in array1.How can I get output like below when mapping array2?

  Item does'nt exists
  orange 
  apple
reactjs object include arrays javascript
6 Answers

Try this

const array1 = [{
    item: 'orange',
    id: 11
}, {
    item: 'apple',
    id: 12
}]

const array2 = [10, 11, 12]

for (const x of array2) {
   //find element from array
   const searchElem = array1.find((item) => item.id == x)
   
   if (searchElem) {
        console.log(searchElem.item + " for " + x)
    } else {
        console.log("Item doesn't exists for", x)
    }

}

user_116290880

You can easily achieve this result using map and find

const array1 = [
  { item: "orange", id: 11 },
  { item: "apple", id: 12 },
];
const array2 = [10, 11, 12];

const result = array2.map((id) => {
  const itemFound = array1.find((o) => o.id === id);
  if (itemFound) return `${itemFound.item} for ${itemFound.id}`;
  else return `Item does'nt exists for 10`;
});

console.log(result);

user_91534480

If I understand the question correctly what you want to do is confirm if an object with a certain property exists in Array 1 for each element in Array 2.

If you want to check each and see if it exists you can do this:

const fruits = [
  {item: 'orange', id: 11},{item: 'apple', id: 12}
]

const fruitIds = fruits.map((fruit) => fruit.id);

const ids = [10, 11, 12]

ids.forEach((id) => { 
  console.log(`${id} exists in fruits: ` + fruitIds.includes(id))
})

Or if you wish to check if there is a fruit for each ID in the array and you only care about true / false if all exist or not then you can do:

const fruits = [
  {item: 'orange', id: 11}, 
  {item: 'apple', id: 12}
]

const fruitIds = fruits.map((fruit) => fruit.id).sort();

const ids = [10, 11, 12];

console.log("There is a fruit for each ID in ID array: ", JSON.stringify(ids) === JSON.stringify(fruitIds))

If this does not answer your question then please edit and try to make your question clearer and I'll do the same with my answer.

Note that the last snippet is just one way to compare arrays or objects in JavaScript.

user_87121680

The easiest way to get common items by comparing two array in JavaScript is using filter() and includes() array functions.

For example:

const array1 = [
      { item: "orange", id: 11 },
      { item: "apple", id: 12 },
];

const array2 = [10, 11, 12];

const matchedArray = array1.filter((item) => array2.includes(item.id));

console.log(matchedArray);

We don't need to use for loop, forEach, map and find functions.

user_72915040

Try this code I think it will solve your problem

  • I have written some comments on javascript code it may help you.

const array1=[{item:'orange', id:11},{item:'apple', id:12}]
const array2=[10,11,12]

function removeDuplicates(array, matchKey) {
    return array.filter((value, index) => {
        return array.indexOf(array.find(value_1 => value_1[matchKey] == value[matchKey])) == index
    });
}

// send "id" parameter if you want to filter array by id
// ex: removeDuplicates(array1, 'id')
const filteredArray1 = removeDuplicates(array1, 'item');

array2.forEach(id => {
    let foundItem = array1.find(itemObj => itemObj.id == id);
    if(foundItem == null) {
        console.log(`Item doesn't exists for ${id}`);
    }else {
        console.log(`${foundItem.item} for ${id}`);
    }
});

user_161355110

Here's a way using Map, though with a bit of tweaking it could use a normal object instead of Map. The map indexes the items in array1 by id and then allows you to look for the item in the map (using has() or get()); if it doesn't exist you can fall back to the default string. ?? is the nullish coalescing operator and it allows you to give a term for the expression should the value before ?? be null or undefined.

const array1 = [{ item: "orange", id: 11 }, { item: "apple", id: 12 }];
const array2 = [10, 11, 12];
const default_string = "Item does'nt exists";

const array1_map = new Map(array1.map((o) => [o.id, o]));

const res = array2.map( (id) => array1_map.get(id)?.item ?? default_string );

console.log(res);

user_144549390
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