void does not accept null if strictNullChecks is enabled

[gdh1995]

Updated: I find a void variable can not be assigned to null null can not be assigned to a void variable if I enable strictNullChecks on lastest TypeScript nodejs package.

But in https://github.com/Microsoft/TypeScript-Handbook/blob/master/pages/Basic%20Types.md#L207, it says:

However, when using the --strictNullChecks flag, null and undefined are only assignable to void and their respective types.

Is there any mistake made by me or the document?

[DanielRosenwasser]

I think you mean that you get an error if you try to assign null to void, which does sound like a bug to me. @mhegazy

[mhegazy]

Do not use void for a type of a variable. use undefined. the only place void makes sense is in the return type of a function to indicate that it returns nothing.

[gdh1995]

@DanielRosenwasser Sorry for my poor English.

I agree the feature that --strictNullChecks prevents null from being returned in a void function, because some function in chrome's extension APIs do checks only for returned undefined and null is treated differently.

Might the document be updated to note this?

[timjb]

I also believe that the documentation is misleading here: It caused me to think that null always is a member of the void type, like undefined. But this is only true if --strictNullChecks is not enabled!

[gdh1995]

This issue seems to be out of date. Now I'm using TypeScript 3.3/3.4 happily.

[wataash]

Fixed in #1053 and #1096 .