Cannot get what I should when doing 'fn.apply(null, arguments)' in the Promise

Question

Here is functional code:

let fn = function() { console.log(arguments) }
let fn2 = function() { fn.apply(null, arguments) }

So after call fn2(1,'t',4) getting Arguments { 0: 1, 1: "t", 2: 4, … } .

But this code:

let def = { }

let p = new Promise((s,f)=>{
    def.s = function() { s.apply(null, arguments) }
    def.f = function() { f.apply(null, arguments) }
})

p.then(function(){
    console.log(arguments)
})

Returning after call def.s(1,'T',2) this Arguments { 0: 1, … } .

Tried in Chrome and Firefox. Am I missing something? Thanks

Answer 1

A promise can resolve only with a single value, and then callbacks are called with exactly one argument. Passing multiple things into resolve or reject is pointless. If you need all of them, pass them as a tuple value, as elements of an array.