'arguments' object is not ALWAYS updated

[nobso]

Hi @nzakas ,
First of all, thank you so much for sharing your knowledge.

The arguments object is always updated in nonstrict mode to reflect changes in the named parameters. Thus, when first and second are assigned new values, arguments[0] and arguments[1] are updated accordingly, making all of the === comparisons resolve to true.

There is a nuance and it looks like 'arguments' object is not ALWAYS updated in non-strict mode if there is a missing parameter.

function mixArgs (first) {
    console.log(arguments[0]); //  undefined
    first = 'c';
    console.log(arguments[0]); //  undefined
}
mixArgs();