promise all map subscriptions code example

Example 1: map with promise.all

//Here i have filmresponse.json() which will return promise so i uses promise.
//all otherwise it won't be possible to run it 

let characterResponse = await fetch('http://swapi.co/api/people/2/')
let characterResponseJson = await characterResponse.json()
let films = await Promise.all(
  characterResponseJson.films.map(async filmUrl => {
    let filmResponse = await fetch(filmUrl)
    return filmResponse.json()
  })
)
console.log(films)

Example 2: promise.all map statement

// Function to fetch Github info of a user.
const fetchGithubInfo = async (url) => {
  console.log(`Fetching ${url}`)
  const githubInfo = await axios(url) // API call to get user info from Github.
  return {
    name: githubInfo.data.name,
    bio: githubInfo.data.bio,
    repos: githubInfo.data.public_repos
  }
}

// Iterates all users and returns their Github info.
const fetchUserInfo = async (names) => {
  const requests = names.map((name) => {
    const url = `https://api.github.com/users/${name}`
    return fetchGithubInfo(url) // Async function that fetches the user info.
     .then((a) => {
      return a // Returns the user info.
      })
  })
  return Promise.all(requests) // Waiting for all the requests to get resolved.
}


fetchUserInfo(['sindresorhus', 'yyx990803', 'gaearon'])
 .then(a => console.log(JSON.stringify(a)))

/*
Output:
[{
  "name": "Sindre Sorhus",
  "bio": "Full-Time Open-Sourcerer ·· Maker ·· Into Swift and Node.js ",
  "repos": 996
}, {
  "name": "Evan You",
  "bio": "Creator of @vuejs, previously @meteor & @google",
  "repos": 151
}, {
  "name": "Dan Abramov",
  "bio": "Working on @reactjs. Co-author of Redux and Create React App. Building tools for humans.",
  "repos": 232
}]
*/