Before You File a Proposal Please Confirm You Have Done The Following...

• I havesearched for related issues and found none that match my proposal.
• I have searched thecurrent rule list and found no rules that match my proposal.
• I haveread the FAQ and my problem is not listed.

My proposal is suitable for this project

• My proposal specifically checks TypeScript syntax, or it proposes a check that requires type information to be accurate.
• My proposal is not a "formatting rule"; meaning it does not just enforce how code is formatted (whitespace, brace placement, etc).
• I believe my proposal would be useful to the broader TypeScript community (meaning it is not a niche proposal).

Description

TypeScript now supportsDisposables: objects that have some "dispose" behavior when they go out of scope.

It's important to useusing and notconst/let when using those objects, otherwise the automatic cleanup does not happen and you would leak resources.

Fail Cases

In this case we are opening a file through an API that expects to be disposed, but we are not using it as such. ThereadConfig function will thus leak resources associated to the opened file.

declarefunctionopenFile(url:string):Disposable&MyFileAPI;functionreadConfig(){constconfigFile=openFile("./configFile");returnconfigFile.contentsAsJson();}

Pass Cases

In this case we are properly disposing the file resource.

declarefunctionopenFile(url:string):Disposable&MyFileAPI;functionreadConfig(){  usingconfigFile=openFile("./configFile");returnconfigFile.contentsAsJson();}

Additional Info

This is the equivalent torequire-await, but for Disposables rather than Thenables.