[3 Bugs] Weird behaviour of one element array and array of arrays in Dict and JS

1) 1 — E L E M E N T A R R A Y T O J S
I have the following [dict] content:
{
"key" : [ {
"subkey" : 0
} ]
}
When I ask in js:
Array.isArray( dict.get("key") );
I am getting 0.
But I should get 1, because "key" actually IS an array!

This is extremely frustrating because sometimes I need to remove items/keys from my arrays in dict, I end with 1-element array and the code stops working because it expects an array.

I know that I could use an array check like
var key = Array.isArray(key) ? key : [key]

But why should I if actually IT IS an array?

2) S E N D I N G 1 – E L E M A R R A Y F R O M J S T O D I C T
The same behaviour provides the following problem:
In JS I write:
dict.set("key", [ elem ] );
And in Dict I get:
{
"key" : "elem"
}
instead of:
{
"key" : [ "elem" ]
}

What is the reasoning behind that? Is it a bug? Or am I doing something wrong?
One of the workarounds at the end are written here: https://x37v.com/x37v/max/dict-object/ (with append. method) but at best it creates 2-element array and the second element is empty ("" or undefined).

3) A R R A Y O F A R R A Y S
This structure should be possible in JSON:
{
"key" : [ [ 0, 1, 2 ], [ "a", "b", "c" ] ]
}
it could be saved in a Dict etc and error is not reported.
But when I try to access it by JS:
var key = dict.get( "key[0][1]" );
then Max crashes!

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I would appreciate any suggestions, advices or comments about this topic! Thank you!