Version 9 does not recursively camelCase keys in nested objects when using union with null

[yonex]

Hello,

I recently upgraded camelcase-keys from version 8.0.2 to 9.1.0 and encountered an issue where nested object keys are not being camelCased recursively when using a union type with null.

Example Code:

Here's a TypeScript example to illustrate the issue:

type MyType = {
  foo_bar: {
    foo_prop: string;
  } | null;
};

type MyTypeCamel = CamelCaseKeys<MyType, true>;

In version 8.0.2, the MyTypeCamel would be:

{
  fooBar: {
    fooProp: string;
  } | null;
}

However, in version 9.1.0, it becomes:

{
  fooBar: {
    foo_prop: string;
  } | null;
}

It is worth noting that this issue does not occur when the nested object type is not unioned with null.

Is this a known issue, or is there a new configuration setting that I am not aware of? I would appreciate your assistance on this matter.

Thank you!

[sindresorhus]

// @yutak23

[yonex]

@yutak23 @sindresorhus Thank you for the prompt resolution of the issue! I've updated to version 9.1.2 in my own project and can confirm that the issue has been resolved. I really appreciate the quick turnaround.