nestedObjects.js

var nestedObject = {
  speakers: [{name:"Elie"},{name:"Tim"},{name:"Matt"}],
  data: {
    continents: {
      europe: {
        countries: {
          switzerland: {
            capital: "Bern",
            population: 8000000
          }
        }
      }
    },
    languages: {
      spanish: {
          hello: "Hola"
      },
      french: {
          hello: "Bonjour"
      }
    }
  }
};

function addLanguage(language, halloLanguage){
  nestedObject.data.languages[language] = {
    hello: halloLanguage
  };
}



function removeLanguage(language){
  delete nestedObject.data.languages[language];
}

addLanguage('Russian', 'Darova');

function addCountry(country, capital, population){
  nestedObject.data.continents.europe.countries[country] = {
    capital: capital,
    population: population
  };
}

addCountry('Russia', 'Moscow', 145000000);

function removeCountry(country){
  delete nestedObject.data.continents.europe.countries[country];
}

removeCountry('switzerland');


function addSpeaker(speakerName){
  nestedObject.speakers.push({name: speakerName});
}

addSpeaker('Krasavchik');


function removeSpeaker(speakerName){
  let new_speakers = nestedObject.speakers.filter(el => el.name !== speakerName);
  nestedObject.speakers = new_speakers;
}

removeSpeaker('Matt');

console.log(nestedObject.speakers);
console.log(nestedObject.data.languages);
console.log(nestedObject.data.continents.europe.countries);

function removeSpeaker(speakerName){
let new_speakers = nestedObject.speakers.filter(function(el) {
return el.name !== speakerName;
});
nestedObject.speakers = new_speakers
}