How to read function parameters in API document?

Question

https://developer.mozilla.org/ko/docs/Web/JavaScript/Reference/Global_Objects/Error#Syntax

new Error([message[, fileName[,lineNumber]]])

I always wondering what [ ... [, ... [, ...]]]] means.

It seemed not arrays because it has "," inside of "[...]"

Answer 1

every [...] means its content is optional (only when describing a function signature somewhere, this ain't valid code)

so new Error([message[, fileName[,lineNumber]]])

means new Error();
or new Error(message);
or new Error(message, fileName);
or new Error(message, fileName, lineNumber);

it does not allow for something like new Error(lineNumber);