Front end interview tests

Promise.js

var p1=new Promise(resolve => {
    console.log(1)
    resolve(2)
})
var p2=new Promise(resolve => {
    console.log(3)
    resolve(p1)
})
p1.then(re => {
    console.log(re)    
})
p2.then(re => {
    console.log(re)
})

/*===============================
1
3
2
2
Promise {<resolved>: undefined}
=================================*/