Question 170296 in Javascript Question posted in
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Do both arrays have the same ids?

By default, I have arrays with the name of the continents.

europe= [];
northAmerica = [];
southAmerica = [];
asia = [];

And i have two arrays with some data

arr1 = [1,3];

arr2 = [
  { country: "Brazil", id: 1, continent: "southAmerica" },
  { country: "Germany", id: 2, continent: "europe" },
  { country: "India", id: 3, continent: "asia" },
  { country: "China", id: 4, continent: "asia" },
];

If the id matches in the arrays, I need to send the string obj.country to the corresponding array of the continent.

I tried like this:

arr2.map((item) => {
        if (arr1.find((id) => id === item.id)) {
          if (item.continent === "southAmerica") {
            southAmerica.push(item.country);
          }
          if (item.continent === "asia") {
            asia.push(item.country);
          }
        }
      });

But only the last value is sent to the arrays.

Tags:

3

Answers


  1. 0 
    const arr1Set = new Set(arr1);
let myArr = []
// Check if any object in arr2 has an ID that is also in arr1
const containsIdenticalIds = arr2.some(obj => {
    if (arr1Set.has(obj.id)) {
        myArr.push(obj.country)
    }
});


console.log(myArr); // Output: true
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  2. 0

    You want to use an object to make accessing the arrays a lot easier. You want to use forEach and includes.

    const continents = {
  europe: [],
  northAmerica: [],
  southAmerica: [],
  asia: [],
};

const arr1 = [1,3];

const arr2 = [
  { country: "Brazil", id: 1, continent: "southAmerica" },
  { country: "Germany", id: 2, continent: "europe" },
  { country: "India", id: 3, continent: "asia" },
  { country: "China", id: 4, continent: "asia" },
];

arr2.forEach(data => {
  if (arr1.includes(data.id)) {
    continents[data.continent].push(data.country);
  }
});

console.log(continents);

    using reduce

    const arr1 = [1,3];

const arr2 = [
  { country: "Brazil", id: 1, continent: "southAmerica" },
  { country: "Germany", id: 2, continent: "europe" },
  { country: "India", id: 3, continent: "asia" },
  { country: "China", id: 4, continent: "asia" },
];

const continents = arr2.reduce((continents, data) => {
  if (arr1.includes(data.id)) {
    continents[data.continent].push(data.country);
  }
  return continents;
}, {
  europe: [],
  northAmerica: [],
  southAmerica: [],
  asia: []
});

console.log(continents);
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  3. 0

    Do it like this.

    const continents = {
  europe: [],
  northAmerica: [],
  southAmerica: [],
  asia: []
};


arr1 = [1, 3];

arr2 = [
  { country: "Brazil", id: 1, continent: "southAmerica" },
  { country: "Germany", id: 2, continent: "europe" },
  { country: "India", id: 3, continent: "asia" },
  { country: "China", id: 4, continent: "asia" },
];

arr1.forEach(_id => {
  arr2.find(obj => {
    if (obj.id === _id) {
      continents[obj.continent].push(obj.country);
      return;
    }
  });
});

console.log(continents);
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