javascript - promise handling exception in express

Question

sms_code(userInfo).then(function(data){
    return res.json(data);
})
.then(function(data){
    return res.json(data);
})
.catch(next);

Why

catch(function(err){
    next(err)
})

can be abbreviated to

.catch(next);

Answer 1

catch(function(err){
    next(err)
})

equals

catch(next)

function next(err){

}

Do you think it’s okay?

Answer 2

setTimeout(function(){
    doSomeSth()
},1000)

setTimeout(doSomeSth,1000);