'use strict';

const cities = {

beijing: { name: 'Beijing' },

kiev: { name: 'Kiev' },

london: { name: 'London' },

baghdad: { name: 'Baghdad' },

};

const capitalOf = new WeakMap();

capitalOf.set(cities.beijing, 'People\'s Republic of China');

capitalOf.set(cities.kiev, 'Ukraine');

capitalOf.set(cities.london, 'United Kingdom');

capitalOf.set(cities.baghdad, 'Iraq');

delete cities.london;

capitalOf.delete(cities.baghdad);

console.dir({ cities, capitalOf });