const urls = ['url1', 'url2', 'url3'];

​

function fakeFetch(url, params = '-') {

  // этот вывод в консоль покажет порядок вызовов с их входящими параметрами

  console.log(`fakeFetch to: ${url} with params: ${params}`);

  return new Promise(resolve => {

    setTimeout(() => resolve(`${url} is DONE`), 1000);

  })

};

​

function reduceWay(callback) {

    urls.reduce((accum, item) => {

        return accum

            .then(res => fakeFetch(item, res))

    }, Promise.resolve())

        .then(result => callback(result));

}

​

reduceWay(result => console.log(`result: ${result}`))

​