promise-all-vs-fetch-one-by-one-comparison.js

import fetch from 'node-fetch';

const fetchUserDetailsById = async (id) => {
    const data = await fetch(`https://jsonplaceholder.typicode.com/users/${id}`)
    return await data.json()
}

const userIdsToFetch = [1,2];

const fetchTodosById = async (id) => {
    const data = await fetch(`https://jsonplaceholder.typicode.com/todos/${id}`)
    return await data.json()
}

const todoIdsToFetch = [6,7];

const promisesToFetch = [
    ...userIdsToFetch.map(userId => fetchUserDetailsById(userId)),
    ...todoIdsToFetch.map(todoId => fetchTodosById(todoId)),
]

const getDataParallel = async () => {
    console.time('getDataAsync')
    try {
        const data = await Promise.all(promisesToFetch)
        data.forEach((el) => console.log(el))
    } catch (error) {
        console.log(`Error: ${error}`)
    }
    console.timeEnd('getDataAsync')
}

getDataParallel()


const getDataOneByOne = async () => {
    console.time('getDataOneByOne')
    try {
        const user1 = await fetchUserDetailsById(1)
        const user2 = await fetchUserDetailsById(2)
        const todo1 = await fetchTodosById(1)
        const todo2 = await fetchTodosById(2)
    } catch (error) {
        console.log(`Error: ${error}`)
    }
    console.timeEnd('getDataOneByOne')
}

getDataOneByOne()

/* 
  {id: 1, name: 'Leanne Graham', username: 'Bret', email: 'Sincere@april.biz', address: {…}, …}
  {id: 2, name: 'Ervin Howell', username: 'Antonette', email: 'Shanna@melissa.tv', address: {…}, …}
  {userId: 1, id: 6, title: 'qui ullam ratione quibusdam voluptatem quia omnis', completed: false}
  {userId: 1, id: 7, title: 'illo expedita consequatur quia in', completed: false}
  getDataAsync: 237.945068359375 ms
  getDataAsync: 237.954ms
  getDataOneByOne: 655.406005859375 ms
  getDataOneByOne: 655.506ms
*/