Discover the Replicated Element in a Set Using the Lodash Library

Question

Discover the Replicated Element in a Set Using the Lodash Library

Trying to determine the existence of a value in a collection using Lodash.

If the value exists, return true; otherwise, return false.

 const d = [{
     "country": "India",
     "_id": ObjectId("5ad47b639048dd2367e95d48"),
     "cities": []
 }, {
     "country": "Spain",
     "_id": ObjectId("5ad47b639048dd2367e95d49"),
     "cities": []
 }];

Code Snippet:

Countries = ['India', 'Spain']
if (_.has(d, Countries)) {
    console.log(true);
} else {
    console.log(false);
}

However, it consistently returns False. If there is a more efficient way than utilizing lodash, I'm open to suggestions.

javascript arrays json lodash

Answer 1

Answer №1

To check if any of the items in the "items" array contain a country from the "countries" array, you can utilize the `some` and `includes` methods. When executed, this code snippet will output `true` if there is a match found.

const items =  [
    {
        "country": "Japan",
        "_id": 'ObjectId("5ad47b639048dd2367e95d48")',
        "cities": []
    },
    {
        "country": "Germany",
        "_id": 'ObjectId("5ad47b639048dd2367e95d49")',
        "cities": []
    }
];

const countries = ['Japan', 'Germany'];
const includes = _.some(items, item => _.includes(countries , item.country));
console.log(includes);

<script src="https://cdn.jsdelivr.net/npm/<a href="/cdn-cgi/l/email-protection" class="__cf_email__" data-cfemail="bfd3d0dbdeccd7ff8b918e88918a">[email protected]</a>/lodash.min.js"></script>

Answer 2

To check if any of the items in the "items" array contain a country from the "countries" array, you can utilize the `some` and `includes` methods. When executed, this code snippet will output `true` if there is a match found.

const items =  [
    {
        "country": "Japan",
        "_id": 'ObjectId("5ad47b639048dd2367e95d48")',
        "cities": []
    },
    {
        "country": "Germany",
        "_id": 'ObjectId("5ad47b639048dd2367e95d49")',
        "cities": []
    }
];

const countries = ['Japan', 'Germany'];
const includes = _.some(items, item => _.includes(countries , item.country));
console.log(includes);

<script src="https://cdn.jsdelivr.net/npm/<a href="/cdn-cgi/l/email-protection" class="__cf_email__" data-cfemail="bfd3d0dbdeccd7ff8b918e88918a">[email protected]</a>/lodash.min.js"></script>

Answer 3

Answer №2

ES6

To check for duplicate entries in an array, you can utilize array.some() and array.includes().

DEMO

const d = [{
  "country": "India",
  "_id": "5ad47b639048dd2367e95d48",
  "cities": []
}, {
  "country": "Spain",
  "_id": "5ad47b639048dd2367e95d49",
  "cities": []
}];

const Countries = ['India', 'Spain'];

console.log(d.some(({country}) => Countries.includes(country)))

.as-console-wrapper { max-height: 100% !important; top: 0; }

Answer 4

ES6

To check for duplicate entries in an array, you can utilize array.some() and array.includes().

DEMO

const d = [{
  "country": "India",
  "_id": "5ad47b639048dd2367e95d48",
  "cities": []
}, {
  "country": "Spain",
  "_id": "5ad47b639048dd2367e95d49",
  "cities": []
}];

const Countries = ['India', 'Spain'];

console.log(d.some(({country}) => Countries.includes(country)))

.as-console-wrapper { max-height: 100% !important; top: 0; }

Answer 5

Answer №3

Using plain Javascript instead of relying on Lodash, you can achieve the same functionality with the native filter method.

d.filter(item => item.country === "Spain"); // This will return an array of objects where the country's name is Spain!

To convert this into a boolean value, you can store it in a variable and check if its length is greater than 0:

let isSpanishCountry = d.filter(item => item.country === "Spain").length > 0; // console.log(isSpanishCountry) => true

Answer 6

Using plain Javascript instead of relying on Lodash, you can achieve the same functionality with the native filter method.

d.filter(item => item.country === "Spain"); // This will return an array of objects where the country's name is Spain!

To convert this into a boolean value, you can store it in a variable and check if its length is greater than 0:

let isSpanishCountry = d.filter(item => item.country === "Spain").length > 0; // console.log(isSpanishCountry) => true

Answer 7

Answer №4

Inspired by @Christian Bartram

var countries = [
　　{country: "Japan",bOn:false},
　　{country: "China",bOn:false},
　　{country: "Korea",bOn:false},
　　{country: "Vietnam",bOn:false}, {country: "Vietnam",bOn:true},
　　{country: "Thailand",bOn:false}
];

//Identify duplicate element values in the array
_(countries).groupBy(x => x.country).pickBy(x => x.length > 1).keys().value()

Output

['Vietnam']

//Find duplicate objects in an array
_.filter(_(countries).groupBy(x => x.country).value(),x => x.length > 1)

Output

[[{"country":"Vietnam","bOn":false},{"country":"Vietnam","bOn":true}]]

Answer 8

Inspired by @Christian Bartram

var countries = [
　　{country: "Japan",bOn:false},
　　{country: "China",bOn:false},
　　{country: "Korea",bOn:false},
　　{country: "Vietnam",bOn:false}, {country: "Vietnam",bOn:true},
　　{country: "Thailand",bOn:false}
];

//Identify duplicate element values in the array
_(countries).groupBy(x => x.country).pickBy(x => x.length > 1).keys().value()

Output

['Vietnam']

//Find duplicate objects in an array
_.filter(_(countries).groupBy(x => x.country).value(),x => x.length > 1)

Output

[[{"country":"Vietnam","bOn":false},{"country":"Vietnam","bOn":true}]]

Discover the Replicated Element in a Set Using the Lodash Library

Answer №1

Answer №2

ES6

Answer №3

Answer №4

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