async_fetch.js

//========================= utils ========================================
const url = n => `https://api.mathjs.org/v4/?expr=sqrt(${n})`;
const sumalos = arr => arr.reduce( (acc, v) =>  acc + v, 0);
const res =  r => r.json();
//========================================================================
// get sqrt using api.mathjs
async function getSqrt(number) {
	const request = await fetch(url(number))
	return request.json()
}
//========================================================================
async function getSumSqrt(numbers = [1,4,9,16]) {	
	const n1 = await fetch( url(numbers[0]) ).then(res);
	const n2 = await fetch( url(numbers[1]) ).then(res);
	const n3 = await fetch( url(numbers[2]) ).then(res);
	const n4 = await fetch( url(numbers[3]) ).then(res);
	console.log(sumalos([n1, n2, n3, n4])); // 10
}

//========================================================================
// same feature as previous but using Promise.all (works for whatever array size)
async function sumSqrts(numbers = [1,4,9,16]) {	
 	const myPromises = numbers.map( async (num) =>  await fetch(url(num)).then(res) );	
	const myResultArray = await Promise.all(myPromises);
	console.log(sumalos(myResultArray)) // 10 by defualt
}


getSqrt(324).then(console.log)

// notice that every async function will always return a promise.