How to loop through an array of Objects, Keep count of one of the Object's value and then retur-CodePudding

I have been trying to get the top n languages in an array of country objects and return the top n languages as an object of the language and it's count value. I tried using two loops, one nested in the other but I got stuck. Here is a short example of the array of country Objects...

const countries = [
{
 name: 'Afghanistan',
 capital: 'Kabul',
 languages: ['Pashto', 'Uzbek', 'Turkmen'],
 population: 27657145,
 flag: 'https://restcountries.eu/data/afg.svg',
 currency: 'Afghan afghani'
},
{
 name: 'Åland Islands',
 capital: 'Mariehamn',
 languages: ['Swedish'],
 population: 28875,
 flag: 'https://restcountries.eu/data/ala.svg',
 currency: 'Euro'
},
{
 name: 'Albania',
 capital: 'Tirana',
 languages: ['Albanian'],
 population: 2886026,
 flag: 'https://restcountries.eu/data/alb.svg',
 currency: 'Albanian lek'
},
{
 name: 'Algeria',
 capital: 'Algiers',
 languages: ['Arabic'],
 population: 40400000,
 flag: 'https://restcountries.eu/data/dza.svg',
 currency: 'Algerian dinar'
},
{
 name: 'American Samoa',
 capital: 'Pago Pago',
 languages: ['English', 'Samoan'],
 population: 57100,
 flag: 'https://restcountries.eu/data/asm.svg',
 currency: 'United State Dollar'
},
{
 name: 'Andorra',
 capital: 'Andorra la Vella',
 languages: ['Catalan'],
 population: 78014,
 flag: 'https://restcountries.eu/data/and.svg',
 currency: 'Euro'
},
{
 name: 'Angola',
 capital: 'Luanda',
 languages: ['Portuguese'],
 population: 25868000,
 flag: 'https://restcountries.eu/data/ago.svg',
 currency: 'Angolan kwanza'
},
{
 name: 'Anguilla',
 capital: 'The Valley',
 languages: ['English'],
 population: 13452,
 flag: 'https://restcountries.eu/data/aia.svg',
 currency: 'East Caribbean dollar'
},const countries = [
{
 name: 'Afghanistan',
 capital: 'Kabul',
 languages: ['Pashto', 'Uzbek', 'Turkmen'],
 population: 27657145,
 flag: 'https://restcountries.eu/data/afg.svg',
 currency: 'Afghan afghani'
},
{
 name: 'Åland Islands',
 capital: 'Mariehamn',
 languages: ['Swedish'],
 population: 28875,
 flag: 'https://restcountries.eu/data/ala.svg',
 currency: 'Euro'
},
{
 name: 'Albania',
 capital: 'Tirana',
 languages: ['Albanian'],
 population: 2886026,
 flag: 'https://restcountries.eu/data/alb.svg',
 currency: 'Albanian lek'
},
{
 name: 'Algeria',
 capital: 'Algiers',
 languages: ['Arabic'],
 population: 40400000,
 flag: 'https://restcountries.eu/data/dza.svg',
 currency: 'Algerian dinar'
},
{
 name: 'American Samoa',
 capital: 'Pago Pago',
 languages: ['English', 'Samoan'],
 population: 57100,
 flag: 'https://restcountries.eu/data/asm.svg',
 currency: 'United State Dollar'
},
{
 name: 'Andorra',
 capital: 'Andorra la Vella',
 languages: ['Catalan'],
 population: 78014,
 flag: 'https://restcountries.eu/data/and.svg',
 currency: 'Euro'
},
{
 name: 'Angola',
 capital: 'Luanda',
 languages: ['Portuguese'],
 population: 25868000,
 flag: 'https://restcountries.eu/data/ago.svg',
 currency: 'Angolan kwanza'
},
{
 name: 'Anguilla',
 capital: 'The Valley',
 languages: ['English'],
 population: 13452,
 flag: 'https://restcountries.eu/data/aia.svg',
 currency: 'East Caribbean dollar'
}]

And this is what I'm expecting to get


// My output should look like this
console.log(mostSpokenLanguages(countries, 5))
/*[
{country: 'English',count:91},
{country: 'French',count:45},
{country: 'Arabic',count:25},
{country: 'Spanish',count:24},
{country:'Russian',count:9}
]*/

This is what I tried


const mostSpokenLanguage = (arr, count) => {
let languageCountObjArr = [];
let languagesArr = arr.map(countryObj => countryObj.languages);
console.log('Languages Array', languagesArr);
languagesArr.forEach(languageArr => {
 for (let i = 0; i < languageArr.length; i  ) {
   /* I GOT STUCK HERE
     let langObj = {
     country: languageArr[i],
     count: 1
   };
   if (languageCountObjArr[i].country === languageArr[i]) {
     let
   }*/
   languageCountObjArr.push(langObj);
 }
});
languageCountObjArr = languageCountObjArr.slice(count);
return languageCountObjArr;
};

I just started JavaScript a couple of weeks now and this stuff has been giving me worries. Please I would be very happy if I can get the answer to this question.

CodePudding user response：

You can do:

const countries = [{name: 'Afghanistan',capital: 'Kabul',languages: ['Pashto', 'Uzbek', 'Turkmen'],population: 27657145,flag: 'https://restcountries.eu/data/afg.svg',currency: 'Afghan afghani',},{name: 'Åland Islands',capital: 'Mariehamn',languages: ['Swedish'],population: 28875,flag: 'https://restcountries.eu/data/ala.svg',currency: 'Euro',},{name: 'Albania',capital: 'Tirana',languages: ['Albanian'],population: 2886026,flag: 'https://restcountries.eu/data/alb.svg',currency: 'Albanian lek',},{name: 'Algeria',capital: 'Algiers',languages: ['Arabic'],population: 40400000,flag: 'https://restcountries.eu/data/dza.svg',currency: 'Algerian dinar',},{name: 'American Samoa',capital: 'Pago Pago',languages: ['English', 'Samoan'],population: 57100,flag: 'https://restcountries.eu/data/asm.svg',currency: 'United State Dollar',},{name: 'Andorra',capital: 'Andorra la Vella',languages: ['Catalan'],population: 78014,flag: 'https://restcountries.eu/data/and.svg',currency: 'Euro',},{name: 'Angola',capital: 'Luanda',languages: ['Portuguese'],population: 25868000,flag: 'https://restcountries.eu/data/ago.svg',currency: 'Angolan kwanza',},{name: 'Anguilla',capital: 'The Valley',languages: ['English'],population: 13452,flag: 'https://restcountries.eu/data/aia.svg',currency: 'East Caribbean dollar',},]

const countriesHash = countries.reduce((a, { languages }) =>
  (languages.forEach((l) => (a[l] = (a[l] || 0)   1)), a), {})

const result = Object.entries(countriesHash)
  .map(([country, count]) => ({ country, count }))
  .sort((a, b) => b.count - a.count)

console.log(result)

CodePudding user response：

A more dynamic approach to use based on array of obj and its property and get the count based on its number of occurences.

const countries = [
{
 name: 'Afghanistan',
 capital: 'Kabul',
 languages: ['Pashto', 'Uzbek', 'Turkmen']
},
{
 name: 'Åland Islands',
 capital: 'Mariehamn',
 languages: ['Swedish']
},
{
 name: 'Albania',
 capital: 'Tirana',
 languages: ['Albanian']
},
{
 name: 'Algeria',
 capital: 'Algiers',
 languages: ['Arabic']
},
{
 name: 'American Samoa',
 capital: 'Pago Pago',
 languages: ['English', 'Samoan']
},
{
 name: 'Andorra',
 capital: 'Andorra la Vella',
 languages: ['Catalan']
},
{
 name: 'Angola',
 capital: 'Luanda',
 languages: ['Portuguese']
},
{
 name: 'Anguilla',
 capital: 'The Valley',
 languages: ['English']
},
{
 name: 'Afghanistan',
 capital: 'Kabul',
 languages: ['Pashto', 'Uzbek', 'Turkmen']
},
{
 name: 'Åland Islands',
 capital: 'Mariehamn',
 languages: ['Swedish']
},
{
 name: 'Albania',
 capital: 'Tirana',
 languages: ['Albanian']
},
{
 name: 'Algeria',
 capital: 'Algiers',
 languages: ['Arabic']
},
{
 name: 'American Samoa',
 capital: 'Pago Pago',
 languages: ['English', 'Samoan']
},
{
 name: 'Andorra',
 capital: 'Andorra la Vella',
 languages: ['Catalan']
},
{
 name: 'Angola',
 capital: 'Luanda',
 languages: ['Portuguese']
},
{
 name: 'Anguilla',
 capital: 'The Valley',
 languages: ['English']
}]

function groupBy(objectArray, property) { 
    return objectArray.reduce(function (acc, obj) {
     let key = obj[property]
     if (!acc[key]) {
      acc[key] = {}
      acc[key][property] = key
      acc[key].count = 0
     }
     acc[key].count  
     return acc 
     }, {})
    }
    
const result = groupBy(countries, 'name')
console.log(result)