async-await Example

async-await.js

function slowFunction() {
    return new Promise((resolve, reject) => {

        // This is where your API call would happen. Wherever you are able to access the required value, call resolve(VALUE)

        setTimeout(() => {
            resolve({
                'key': 'ans'
            });
        }, 2000);
    })
}

async function main() {

    let ans = {
        'key': 'val'
    };

    ans = await slowFunction();
    console.log(ans); // Note that the previously set value should not be displayed dispite having a 'slow' function in between.
}

main();