var a = new Promise((resolve,reject)=>{
    // Do someting
    resolve('data');
    })
    .then((data)=>{
        console.log(data)
        // Do something
        // Delay 5000ms
        return new Promise((resolve,reject)=>{
            setTimeout(()=>{
                resolve('new data');
            },3000)
        })
    })
    .then((data)=>{
        console.log(data)
        throw new Error('Throw error like reject(error)')
    })
    .catch(console.log.bind(console))