Overload Array.filter() to exclude nully when using Boolean #31551

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1. dragomirtitian commented on May 23, 2019

   

   Titian Cernicova-Dragomir (dragomirtitian)

   on May 23, 2019

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   Duplicate of #16655 I believe. Which was included and then reverted due to it causing breaking changes. Comment

   This was reverted due to it causing a breaking change in 3.5. The simple repro looks like this:

   declare const Bullean: {
       new(value?: any): Boolean;
       <T>(value?: T): value is Exclude<T, false | null | undefined | '' | 0>;
   };
   
   declare const arr: any[];
   // Was any[], now (3.5) unknown[]
   const arr2 = arr.filter(Bullean);

   There might be something wrong in generic inference, but it's not yet clear. We'll need this scenario to work before adding it back in.

   👍React with 👍1Reacted by Ryan Cavanaugh
2. Ryan Cavanaugh (RyanCavanaugh)

   added

   DuplicateAn existing issue was already createdAn existing issue was already created

   on May 23, 2019
3. TypeScript Bot (typescript-bot)

   closed this as completedon May 25, 2019
4. typescript-bot commented on May 25, 2019

   

   TypeScript Bot (typescript-bot)

   on May 25, 2019

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   This issue has been marked as a 'Duplicate' and has seen no recent activity. It has been automatically closed for house-keeping purposes.
5. microsoft

   locked as resolved and limited conversation to collaborators on Oct 21, 2025