Discrepancy in JSDoc and implementation in express.Router(), parameter required by documentation is actually optional

[pubmikeb]

At the very beginning of my router (Express.js) there are the following lines of code:

"use strict";

let express = require('express');
let router = express.Router();

IntelliJ IDEA returns warning Invalid number of arguments regarding let router = express.Router();.
I checked the official documentation of Express.js (see express.Router), and there is the same line of code.

The IntelliJ IDEA response:

JSDoc defines special syntax for documenting which parameters are optional and IDEA respects this syntax.

The function in express.js is documented here as having a non-optional parameter, while the implementation makes it optional.

Please, have a look if there is a need to synchronize the documentation and implementation.

Details:
https://youtrack.jetbrains.com/issue/WEB-31658

[LinusU]

Good catch 👍

PR is up here: #3599

[pubmikeb]

So, was it the problem with documentation or implementation?

[LinusU]

It was a problem with the JSDoc annotations, the options argument wasn't marked as optional, even though the object is indeed optional.