node uri regex not capturing capture groups - node.js

Question

I know there are a billion regex questions on stackoverflow, but I can't understand why my uri matcher isn't working in node.
I have the following:
var uri = "file:tmp.db?mode=ro"
function parseuri2db(uri){
var regex = new RegExp("(?:file:)(.*)(?:\\?.*)");
let dbname = uri.match(regex)
return dbname
}
I'm trying to identify only the database name, which I expect to be:
After an uncaptured file: group
Before an optional ? + parameters to end of string.
While I'm using:
var regex1 = new RegExp("(?:file:)(.*)(?:\\?.*)");
I thought the answer was actually more like:
var regex2 = new RegExp("(?:file:)(.*)(?:\\??.*)");
With a 0 or 1 ? quantifier on the \\? literal. But the latter fails.
Anyway, my result is:
console.log(parseuri2db(conf.db_in.filename))
[ 'file:tmp.db?mode=ro',
'tmp.db',
index: 0,
input: 'file:tmp.db?mode=ro' ]
Which seems to be capturing the whole string in the first argument, rather than just the single capture group I asked for.
My questions are:
What am I doing wrong that I'm getting multiple captures?
How can I rephrase this to capture my capture groups with names?
I expected something like the following to work for (2):
function parseuri2db(uri){
// var regex = new RegExp("(?:file:)(.*)(?:\\?.*)");
// let dbname = uri.match(regex)
var regex = new RegExp("(?<protocol>file:)(?<fname>.*)(<params>\\?.*)");
let [, protocol, fname, params] = uri.match(regex)
return dbname
}
console.log(parseuri2db(conf.db_in.filename))
But:
SyntaxError: Invalid regular expression: /(?<protocol>file:)(?<fname>.*)(<params>\?.*)/: Invalid group
Update 1
Answer to my first question is that I needed to not capture the ? literal in the second capture group:
"(?:file:)([^?]*)(?:\\??.*)"

Answer 1

That particular node regex library does not support groups.