javascript - Swap tuple elements with destructuring assignments -

i thought swap elements of tuple in place using destructuring assignment follows:

var = [1,2]; [a[1], a[0]] = a;

however, yields [1, 1].

babel compiles as

a[1] = a[0]; a[0] = a[1];

i have thought should compiled as

let tmp0 = a[0]; let tmp1 = a[1]; a[0] = tmp1; a[1] = tmp0;

traceur behaves identically babel. guess specified behavior?

i want swap 2 elements in place. way...

let tmp = a[0]; a[0] = a[1]; a[1] = tmp;

but thought above destructuring assignment supposed let me avoid having do.

i'm capable of reversing order of 2 elements of array, not question. simple a.push(a.shift()), meets criteria of swapping being in-place.

i'm interested here in why destructuring doesn't work way seems ought to.

i'd use function this

let swap = ([a,b]) => [b,a];  swap([1,2]); // => [2,1]

Panthy J