In then Return Create promise of promise.js

const newPromise = new Promise((resolve, reject)=>{
    setTimeout(()=>{resolve('changed')}, 3000)
}).then((data)=>{
    console.log(data)
    //第二個Promise
    return new Promise((resolve, reject)=>{
        setTimeout(()=>{resolve('last ' + data)},2000)
    }).then((lastData)=>{
        return lastData
    })
}).then((data)=>{
    console.log(data) // 'last changed'
})