JSFiddle - React, Tailwind, and code Playground

JavaScript

function HashArray(){
    this.indexKeys = {};
    this.storage = [];
}

HashArray.prototype.addUser = function(name, age){
    //if length is 10, storage.shift(), and delete
    //     delete user from indexKeys
    if (this.storage.length === 10) {
       this.storage.shift();
       delete this.indexKeys[name];
    }
    
    // add user object {name, age} to storage
    // add index of object on storage to indexKeys
    // as {name: indexOnStorage}
    
    this.indexKeys[name] = this.storage.length;
    this.storage.push({name:name, age:age});
};

HashArray.prototype.getPerson = function(name){
    var indexPersonObjLocated = this.indexKeys[name];
    return this.storage[indexPersonObjLocated];
};
HashArray.prototype.getStorage = function(){
    return this.storage;
};
HashArray.prototype.getKeys = function(){
    return this.indexKeys;
};

var coolObj = new HashArray();
coolObj.addUser("White", 24);
coolObj.addUser("Whate", 25);
coolObj.addUser("Plite", 26);