HW/HWJS12/js/script.js

let url = 'https://raw.githubusercontent.com/David-Haim/CountriesToCitiesJSON/master/countriesToCities.json';
let request = new XMLHttpRequest();
request.open("GET", url, true);

request.onreadystatechange = () => {
    if (request.readyState == 4){
        let countriesFromJson = JSON.parse(request.response);
        showCountry(countriesFromJson);

        countrySelect.oninput = () => {
            showCities(countrySelect.value, countriesFromJson);
        }
    }
    
}

request.send()

function showCountry(obj){
    for (let [key,val] of Object.entries(obj)){

        let option = document.createElement('option');
        option.innerText = key
        countrySelect.append(option)
    }
    showCities(countrySelect.value, obj);
}

function showCities(country, object){
    citySelect.innerText = ''
    let citiesFromCurrentCountry = object[country];
    citiesFromCurrentCountry.forEach((item) => {
        let option = document.createElement('option');
        option.innerText = item
        citySelect.append(option)
    });
}

////////////////////////////////////////////////////////fetch basic, fetch improved
let url2 = 'https://swapi.dev/api/people/1/';
let valueCreators = {
    String(value){
        if(value.includes("https://swapi.dev/api/")){
            return `<button>${value}</button>`
        } else {
            return value
        }
    },
    Array(value){
        let str = '';
        value.forEach((item) => {
            item.includes("https://swapi.dev/api/") ? str += `<button>${item}</button>` : str += item
        })
        return str 
    }
}

function createTable(parent, obj){
   
    let str = '<table border="2">';

    for(let [key,value] of Object.entries(obj)){
        let valueCreator = valueCreators[value.constructor.name];
        if (typeof valueCreator === 'function'){                               ///проверяем значение (есть ли для него нужный конструктор)
            str += `<tr><td>${key}</td><td>${valueCreator(value)}</td></tr>`
        } else {
            str += `<tr><td>${key}</td><td>${value}</td></tr>`
        }
    }

    str += '</table>'
    parent.innerHTML += str;
}

let startFetch = function (url,parent){                      ////создает новую таблицу в том элементе где была кнопка
    fetch(url)
    .then(res => res.json())
    .then(luke => createTable(parent, luke))
}

startFetch(url2, container);

container.addEventListener("click", (event) => {
    if(event.target.tagName == 'BUTTON'){
        startFetch(event.target.textContent, event.target.parentElement)
    }
})

// let startFetch = function (url){                      ///// или можно все перезатирать и создавать новую (без наглядной вложенности)
//     fetch(url)                                        ///// только в 72 строке изменить на parent.innerHTML = str;
//     .then(res => res.json())
//     .then(luke => createTable(container, luke))
// }

// startFetch(url2);

// container.addEventListener("click", (event) => {
//     if(event.target.tagName == 'BUTTON'){
//         startFetch(event.target.textContent)
//     }
// })

/////////////////////////////////////////////// my fetch
let url3 = 'https://swapi.dev/api/people/1/';
function myFetch (url){
    return new Promise(function (resolve, reject){
        const xhr = new XMLHttpRequest();
        xhr.open("GET", url, true);
        xhr.onreadystatechange = () => {

            if(xhr.readyState == 4){             ///проверяем закончился ли запрос
                if (xhr.status == 200){
                    resolve(JSON.parse(xhr.response))
                } else if (xhr.onerror || xhr.status != 200){
                    reject(new Error(`i have error for you ${xhr.status} ${xhr.statusText}`))
                }
            }

        }

        xhr.send()
    })
}

myFetch(url3).then(luke => console.log(luke));
////////////////////race
const delay = ms => new Promise(ok => setTimeout(() => ok(ms), ms));

Promise.race([myFetch(url3), delay(350)]).then(value => console.log(value));