microsoft / microsoft/TypeScript
JSDoc disappeared in overloading with mapped type
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Description
Bug Report
🔎 Search Terms
vscode, jsdoc
🕗 Version & Regression Information
4.1.3
⏯ Playground Link
example 1, bug, no jsdoc:
No JSDoc if overloading in mapped type

example 2, works well:
Has JSDoc if no overloading in mapped type

example 3, bug, no jsdoc:
JSDoc disappeared without overloading

💻 Code
type ApiDict = {
/**
* jsdoc for getString
*/
getString: string;
/**
* jsdoc for getBoolean
*/
getBoolean: boolean;
};
type Api = {
[key in keyof ApiDict]: {
(url: string): ApiDict[key];
(url: string, config: {}): { data: ApiDict[key]; extra: any };
};
};
declare const api: Api;
api.getBoolean('', {});
type ApiDict = {
/**
* jsdoc for getString
*/
getString: string;
/**
* jsdoc for getBoolean
*/
getBoolean: boolean;
};
type Api = {
[key in keyof ApiDict]: {
(url: string, config: {}): { data: ApiDict[key]; extra: any };
};
};
declare const api: Api;
api.getBoolean('', {});
/**
* jsdoc for JsdocDisappearedWithoutOverloading
*/
interface JsdocDisappearedWithoutOverloading {
(url: string): any;
}
declare const jsdocDisappearedWithoutOverloading: JsdocDisappearedWithoutOverloading;
jsdocDisappearedWithoutOverloading('');
🙂 Expected behavior
All of examples has jsdoc
Contributor guide
First steps
- Read the whole issue, then the project's contributing guide.
- Comment on the issue to say you are picking it up — it saves two people doing the same work.
- Fork the repository and make your change on a branch.
- Open a pull request that references the issue number.
Research direction
Start by running the three linked TypeScript Playground examples, comparing the mapped-type overload cases with the working case and the standalone callable interface. Use the provided TypeScript snippets to reproduce the missing JSDoc. Done means all examples retain their declared JSDoc, including mapped types with overloaded call signatures.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- typescript
- Domain
- compilers
- Issue type
- Bug
- Difficulty
- 4/5
- Estimated time
- 3-5 days
- Activity status
- Stale
- Clarity
- Mostly clear
- Newbie friendliness
- 35/100