code from Frontend Development lecture (2020-11-11)

convert_promise_to_async_await.js

const callbackFetch = (url, callback) => {
    // ....
}

const promiseFetch = (url) => {
    return new Promise((resolve, reject) => {
        callbackFetch(url, (result) => {
            if (result.error) { reject(result) }
            else { resolve(result) }
        })
    })
}

// Use wrapped promise
function promiseFetchBestFriendsAddress() {
    return promiseFetch('/api/currentUser')
        .then((currentUser) => promiseFetch(`/api/user/${currentUser.id}/bestFriend`))
        .then((bestFriend) => promiseFetch(`/api/user/${bestFriend.id}/address`))
        .then((addressOfBestFriend) => console.log(addressOfBestFriend))
}
    

// Convert wrapped promise to async function
async function asyncFetchBestFriendsAddress() {
    const currentUser = await promiseFetch('/api/currentUser')
    const bestFriend = await promiseFetch(`/api/user/${currentUser.id}/bestFriend`)
    const bestFriendsAddress = await promiseFetch(`/api/user/${bestFriend.id}/address`)

    console.log(bestFriendsAddress) 
}

help_for_assignment.js

const questions = [
    { whatever: '...' },
    { whatever: '...' },
    { whatever: '...' },
    { whatever: '...' },
]

async function getQuestions() {
    // delay
    return questions
}

react_to_promise.js

const callbackFetch = (url, callback) => {
    // ....
}

const promiseFetch = (url) => {
    return new Promise((resolve) => {
        callbackFetch(url, resolve)
    })
}


function myBestFriendsAddress() {
    return promiseFetch('/api/currentUser')
        .then((currentUser) => promiseFetch(`/api/user/${currentUser.id}/bestFriend`))
        .then((bestFriend) => promiseFetch(`/api/user/${bestFriend.id}/address`))
}

function renderBestFriendsAddressInHTMLPromise ()  {
    myBestFriendsAddress()
        .then((address) => {
            document.innerHTML(JSON.stringify(address))
        })   
}

async function renderBestFriendsAddressInHTMLAsync ()  {
    const address = await myBestFriendsAddress()
    document.innerHTML(JSON.stringify(address))
}