JSFiddle - React, Tailwind, and code Playground

JavaScript

function promiseA(promiseAparam) {
	return new Promise(
		function(resolve, reject) {
    	alert('promiseA('+promiseAparam+')');
			if (promiseAparam) resolve('promiseAresult'); else reject('promiseAerr');
		});
}

function promiseB(promiseBparam) {
	return new Promise(
		function(resolve, reject) {
    	alert('promiseB('+promiseBparam+')');
			if (promiseBparam) resolve('promiseBresult'); else reject('promiseBerr');
		});
}

function getExample() {
    var promiseAparam=true;
    var promiseBparam=true;

		var a = promiseA(promiseAparam);
    var b = a.then(function(resultA) {
        alert('promiseA resolved with '+resultA);
        return promiseB(promiseBparam);
    });
    return Promise.all([a, b]).then(function(values) {
        alert('all resolved with '+values[0]+' , '+values[1]);
        return values[0]+' , '+values[1];
    });
}

getExample().then(function(resultGetExample) {
	alert('getExample resolved with '+resultGetExample);
});