JavaScript function - named parameters issue when skipping an optional parameter

Question

If you run the below code in browser's console:

function named_param(a, b=null, c=5) {
  console.log("a="+a);
  console.log("b="+b);
  console.log("c="+c);
}

named_param(3, c=10)

The output received is:

a=3
b=10
c=5

The output I am looking for, is:

a=3
b=null
c=10

I saw the below two URLs and tried a few workaround but it didn't work

Javascript Function Parameters Not Working

Named parameters in javascript

Let me know the steps I am doing wrong here. Tried the below codes but didn't work: A:

function named_param(a, {b=null, c=5}) {
  console.log("a="+a);
  console.log("b="+b);
  console.log("c="+c);
}

named_param(3, c=10)

B:

function named_param(a, {b=null, c=5}={}) {
  console.log("a="+a);
  console.log("b="+b);
  console.log("c="+c);
}

named_param(3, c=10)

Answer 1

When using the destructuring solution, you must pass an actual object. named_param(3, c=10) simply is invalid syntax (well, it's valid, but it's an assignment to a global c variable that is passed as the second argument - no naming).

function named_param(a, {b=null, c=5}={}) {
  console.log("a="+a);
  console.log("b="+b);
  console.log("c="+c);
}

named_param(3)
named_param(3, {b:"hi"})
named_param(3, {c:10})
named_param(3, {b:"hi", c:10})