Using "||" causes lint errors for nullish checks

[samyarkd]

Describe the bug

Prefer using nullish coalescing operator (`??`) instead of a logical or (`||`), as it is a safer operator.eslint[@typescript-eslint/prefer-nullish-coalescing](https://typescript-eslint.io/rules/prefer-nullish-coalescing)

Using || over ?? for nullish checks is bad practice and it's better to use ?? when possible, also it causes lint errors in projects where a rule to prevent it is configured.

Using || over ?? for nullish checks is bad practice and it's better to use ?? when possible, also it causes lint errors in projects where a rule to prevent it is configured.

To Reproduce
Steps to reproduce the behavior:

• Open a TypeScript/JavaScript file in the project.

• Write code using || for default values, e.g. const value = input || "default".

• Run ESLint or trigger linting in your editor.

• See error from @typescript-eslint/prefer-nullish-coalescing.

Expected behavior
The linter should not throw an error when using the safer nullish coalescing operator (??). Code should be written as const value = input ?? "default" instead of using ||.

OS: Windows

Browser: Edge Version 139.0.3405.111 (Official build) (64-bit)

Additional context
This issue can be fixed by:

• Replacing all || default checks with ?? where appropriate.
• Adding/using the ESLint rule @typescript-eslint/prefer-nullish-coalescing
  to enforce consistent usage across the codebase.

[Yeom-JinHo]

@samyarkd
Thanks for raising this issue and for the clear report.

I opened a PR to address this by replacing || with ?? in places where the fallback is specifically for null/undefined, and by updating the registry generation source so the generated files stay consistent as well.

I intentionally did not blindly replace every ||, because some usages rely on truthy/falsy behavior ("", 0, false) and changing those would alter runtime behavior.

#901