javascript - promise async await without .then callback -

i trying learn , better understand how promises work new async / await keywords there thing confusing.

in article: https://davidwalsh.name/async-await

it says using async , await doesnt require 1 use callback, example:

async function parallel(callback) {     const wait1 = wait(500);     const wait2 = wait(500);     await wait1;     await wait2;     callback( [wait1, wait2] ); } 

if 1 test need define first timeout function serves wait:

var wait = function(time) {      return new promise( function(resolve, reject) {          settimeout(function() {             resolve( math.random() * time );         }, time);      });  }; 

and need call our parallel function , read values:

parallel(function(data) {     console.log('data', data); }); 

the problem if read values - promises objects instead of actual values, remedy problem done:

async function parallel(callback) {     var wait1 = wait(500).then(function(data) {                     wait1 = data;                 });     var wait2 = wait(500).then(function(data) {                     wait2 = data;                 });     await wait1;     await wait2;     callback( [wait1, wait2] ); } 

now work, demo here: https://jsfiddle.net/jp3g2q5k/

but me understand why had use .then callback? supposes callbacks free situation. or maybe knows how alter code work without callbacks.

you resolving promise 'await' keyword. in example be:

const result1 = await wait1; const result2 = await wait2; callback( [result1 , result2 ] );