JSFiddle - React, Tailwind, and code Playground

JavaScript

function World() {
    this.mankind = new Mankind(this);
    this.getName = function(d) {
        return d.name;
    }

    alert('Здесь проживают: ' + this.mankind.city.map(this.getName).join(', '));
}

function Mankind(world) {
    this.people = [
        new Man(this, 'Vasily'),
        new Man(this, 'Alessandra')]
    this.city = this.people.slice()
}

function Man(mankind, name) {
    this.name = name;
}

new World();