Type 'null' is not assignable to type 'T'

I have this generic method

class Foo { 
     public static bar<T>(x: T): T {
         ...
         if(x === null)
             return null; //<------- syntax error
         ...
     }
 }


... //somewhere
const x = Foo.bar<number | null>(1);

I'm getting the syntax error

TS2322: Type 'null' is not assignable to type 'T'.

I'm expecting this to compile because T could be null.

what is the proper way to solve this problem

You have to declare the return type as null or turn off strictNullChecks in your tsconfig

public static bar<T>(x: T): T | null

or you could type null as any e.g.

 return null as any;

Since version 3.9.5, TypeScript enforces strictNullChecks on numbers and strings just to name a few. For example, the following code will throw an error during compilation:

let x: number = null;

To avoid this error you have two options:

• Set strictNullChecks=false in tsconfig.json.
• Declare your variable type as any:

  let x: any = null;
  

You can put

return null!;

It worked for me