vscode jsdoc import module type def not imported

[mjbvz]

From @shivshankar3578 on March 24, 2018 11:9

@VScode:1.21
@node: 8.10

mod.js

/**
 *  @module mod
 */

/**
 * @typedef {Object} foobar
 * @property {String} foo
 * @property {Boolean} [bar] - Optional value
 */

/**
 * 
 * 
 * @param {string} foo 
 * @param {string} bar 
 * @return {foobar} 
 */
function doSomething (foo, bar) {
  console.log(foo, bar);
  // do something
  return {
	foo : foo,
	bar : bar
  }
}

let n = doSomething('a', 'b');

module.exports  = doSomething;

jsdoc.js

const mod = require('./mod');
let n = new mod('a', 'b'); 
console.log(n)

pic-1 n:foobar

then why n:any here

while imported module have foobar return type

Copied from original issue: microsoft/vscode#46463

[mjbvz]

Possibly covered by #14844

[sandersn]

In jsdoc.js, you use new, but without assignments to this properties inside of doSomething, the compiler doesn't recognise it as newable and falls back to any. You'll also get an error if you add // @ts-check at the beginning of the file, because we think that newing a function with no this property assignment is very suspicious.

If you call mod directly as you did on mod.js:27, you will see the correct type for n.