JSdoc 'import type' syntax wrongly transformed when generate declaration from js file

[xlfsummer]

Bug Report

🔎 Search Terms

Import type syntax error after generate .d.ts from js
Import type error after generate .d.ts using JSdoc

🕗 Version & Regression Information

💻 Code

// index.js
/** @type {import('./type').Foo} */
export const foo;

// type.ts
export type Foo = string;

• jsdoc syntax: import-types
• doc: Creating .d.ts Files from .js files

demo repo (using 'import-types' branch, not 'master')

🙁 Actual behavior

output index.d.ts

/** @type {import('./type').Foo} */
export const foo: import('./type').Foo;

import is a method for loading async resource in js/ts, not import a type. it should be transformed to import .. from .. .

🙂 Expected behavior

output index.d.ts

import {Foo} from './type';
/** @type {import('./type').Foo} */
export const foo: Foo;

[fatcerberus]

import is a method for loading async resource in js/ts, not import a type.

import("foo") doesn’t mean that when used in a type position—in that case it means the type of import * as … from "foo", as resolved by TypeScript.

[xlfsummer]

import is a method for loading async resource in js/ts, not import a type.

import("foo") doesn’t mean that when used in a type position—in that case it means the type of import * as … from "foo", as resolved by TypeScript.

Yes. In a type position, we use import(...) to import all exports in another file. When we generate type declaration files, we should not directly copy that from source to dist. We should replace the import(...) by import ... from ... and place it to the top of the output file.

[orta]

JSDoc is used to only give type-hints in TypeScript and JavaScript files, not to direct how the syntax should change. I'm afraid any changes here would be massively breaking to the ecosystem, and break the TypeScript design guides which were mentioned in the issue template.

[xlfsummer]

But I think it's weird to have each single feature works fine but break when use them both. (because import() returns Promise value in ts)

I think maybe we could handle this by replace import() to any? (at least it won't break types)

[andrewbranch]

Working as intended for now, but there’s an issue tracking an investigation into whether we can do this: #44044

(As an aside, it feels slightly weird to me that the JSDoc type tag gets preserved in declaration emit.)

[typescript-bot]

This issue has been marked 'Working as Intended' and has seen no recent activity. It has been automatically closed for house-keeping purposes.