JSDoc-typed node modules require special configuration in consumers to be useful

It looks like an ongoing goal for TS is to recommend JSDoc as the recommended way to give type-checking to raw JS users. As a user I am not a huge fan of this approach but I’ll try to be objective in this issue.

If I write a node module js-lib as raw javascript typed with jsdoc, it will appear as untyped to consumers of my module unless they specifically opt in to JS type checking.

Example:

+-js-lib
| +-index.js
| +-package.json
|
+-ts-consumer
  +-index.ts
  +-package.json
  +-tsconfig.json

js-lib/index.js

/**
 * @param {string} s
 * @returns {number}
 */
module.exports = function test(s) { return parseInt(s) };

js-lib/package.json

{
  "name": "js-lib",
  "main": "index.js"
}

ts-consumer/index.ts

import test = require('../js-lib');
// index.ts(1,23): error TS6143: Module '../js-lib' was resolved to '/Users/jarrad/src/personal/ts-test/lib/js-index.js', but '--allowJs' is not set.

import test = require('js-lib'); // after npm install ../js-lib
// index.ts(1,23): error TS7016: Could not find a declaration file for module 'lib'. '/Users/jarrad/src/personal/ts-test/lib/index.js' implicitly has an 'any' type.
//  Try `npm install @types/lib` if it exists or add a new declaration (.d.ts) file containing `declare module 'lib';

test("test");

ts-consumer/tsconfig.json

{
  "compilerOptions": {
    "strict": true
  }
}

It should be possible for me to make my js-lib usable to Typescript authors without them having to configure their own project with allowJs and checkJs.

[DavidWells]

Hello there! Came here via https://twitter.com/orta/status/1176216539713953793

I recently added Typescript support to my project that is using JSdocs.

My setup is like this:

1. My code is vanilla JS with JSdoc blocks for the types
2. During my build process, I use tsd-jsdoc to convert the JSdocs from the source to a types.d.ts type file. https://github.com/DavidWells/analytics/blob/master/packages/analytics-core/package.json#L31
3. In my package.json, I set the path to where typings lives https://github.com/DavidWells/analytics/blob/master/packages/analytics-core/package.json#L50

It would be super awesome if TS automatically inferred the types from the JSdocs in my built source code. This would streamline things for me 😃

Anywho, thanks for all the great work on TS & the tooling around it. The autocompletion the package has is great!

[akdor1154]

What I am hinting towards is some way of me writing in my library’s package.json that Typescript should indeed dive into its JS files by default, or at least as far as it has to to type the externally visible interface. Strawman: "types": "[jsdoc]". This would (hopefully) void the performance concerns of a full node_modules JS-inference-spree.