JSFiddle - React, Tailwind, and code Playground

JavaScript

var RandomPromiseJob = function(){
	return new Promise(function(resolve,reject){
		var res = Math.round(Math.random()*10)%2;	
		setTimeout(function(){
			if(res){
				resolve(res);
			}else{
				reject(res);
			}
		}, 1000)
	});		
}

var pro = RandomPromiseJob().then(function(data){
	alert('success');
},function(data){
	alert('failed');
});

console.log(pro);