Javascript我如何通过引用传递一个int

Question

Is it possible to pass an int by reference in Javascript?

function myFunction(myval) {
    myval = 3 
}

a = Number(5)
myFunction(a)
console.log(a) //gives 5

How can I get 3, instead of 5?

I found a solution myself like this

function myFunction(myval) {
    myval.val = 3
}

a = { val: 5 }
myFunction(a)
console.log(a.val)

see frederik's comment below which clears my confusion about Number.

Answer 1

Why it gives undefined

Because there is no explicit return from myFunction so it implicitly returns undefined which is being printed in console

 function myFunction(myval) { myval = 3 } a = 5 console.log(myFunction(a)) 

---

In a non-constructor context (ie, without the new operator), Number can be used to perform a type conversion.

 let a = Number(5) console.log(typeof a) 

---

You can do something like this

 function myFunction(myval) { myval.a = 3 } let obj = { a : 5 } myFunction(obj) console.log(obj) 

Answer 2

You cannot pass a number by reference. Here example with object:

 function incrementTheCounter(obj) { obj.counter++; } const a = {counter: 5}; incrementTheCounter(a); console.log(a.counter);