Ultisnips dynamic tabstop generation based on first tabstop - vim

Question

I want a Ultisnips snippet capable of dealing with the following scenario:
const [value1, value2, value3, ...valueN] = await Promise.all([
promise1,
promise2,
promise3,
...,
promiseN,
]);
Based on what I type inside the first square brackets, I want to generate the same amount of new tabstops for each line inside the Promise.all block.
Currently I have this approach, which almost works:
global !p
def insert_lines(txt, start = 2, generate_value = lambda i: f'val{i}'):
count = len(txt.split(','))
lines = ["${" + str(i) + ":" + generate_value(i+1-start) + "}," for i in range(start, count + 2)]
snip.expand_anon("\n".join(lines))
endglobal
post_jump "if snip.tabstop == 0: insert_lines(snip.tabstops[1].current_text, start=2)"
snippet pall "await Promise.all" b
const [${1:...items}] = await Promise.all([
$0
]);
endsnippet
The issue I'm having is that $0 there requires me to jump one time more than I would want to. For example, if I have:
const [foo, bar, baz|] = await Promise.all([
val1,
val2,
val3,
]);
Jumping to the next tabstop, I get:
const [foo, bar, baz|] = await Promise.all([
|val1,
val2,
val3,
]);
Then:
const [foo, bar, baz|] = await Promise.all([
val1,
|val2,
val3,
]);
Then:
const [foo, bar, baz|] = await Promise.all([
val1,
val2,
|val3,
]);
At this point, if I jumped to the next tabstop, I'd expect to reach the end of the snippet, however, what happens is this:
const [foo, bar, baz|] = await Promise.all([
val1,
val2,
val3,|
]);
It kind of makes sense because that's the original position of $0.
Is there any other way to achieve what I want?

Answer 1

I am trying to answer this because I have been involved with Ultisnips for a while and I am not reputed enough to comment.
Why don't you try to place the $0 at like ]);$0(the last line of the code you posted)?
I suppose it should resolve the issue. Let me know.
Edit: Use the stack specifically made for vim and vi related questions for such questions. You can find the site here.