ECMA2015 - promise.js

const promise = new Promise ( ( resolve, reject ) => {
  setTimeout( ()=>{
    resolve( 'success' );
  }, 300);
  setTimeout( () =>{
    reject( 'error' );
  }, 25);
} );
promise.then( (res)=>{
  console.log( res );
})
.catch( (res) => {
  console.log( res );
});