Type instantiation is excessively deep and possibly infinite.ts(2589)

[Micro-sun]

use "react-i18next": "^11.16.3", but have an error "Type instantiation is excessively deep and possibly infinite.ts(2589)"
or have one meet before?

[adrai]

Update all i18next dependencies.
If you still have that issue, please provide a minimal reproducible example repository.

[lucas-dtrn]

Issue

When calling const { t } = useTranslation(); in a React application using i18next, I encountered the following TypeScript error: Type instantiation is excessively deep and possibly infinite

This issue only occurred when the translation JSON file was heavily nested.

Steps to Reproduce

Create a JSON file with deeply nested translation objects (e.g., five or more levels deep).

1. Load the file into your React application using i18next.
2. Import and call useTranslation() in a React component.
3. Observe that TypeScript sometimes reports the error: Type instantiation is excessively deep and possibly infinite

Suggested Solution

Flatten your nested JSON keys using dot notation. For example, convert:

{
  "page_1": {
    "title": "This is a title.",
    "description": "This is a description",
    "button": "Click me!"
  }
}

into:

{
  "page_1.title": "This is a title.",
  "page_1.description": "This is a description",
  "page_1.button": "Click me!"
}

By doing so, TypeScript can handle the translation types without exceeding recursion limits.

Additional Context

• I wrote a custom function to perform the flattening, but there are existing packages that handle this task.
• After flattening, my file with 517 lines (and up to five levels of nesting) worked fine with no errors.
• The exact maximum nested size before hitting the TypeScript limit is unclear, but flattening appears to be a reliable workaround.

Environment

• i18next version: ^15.0.2
• React version: ^18.2.0
• TypeScript version: 5.7.2

Possible Workarounds

• Use an existing package to flatten your JSON files automatically.
• Keep nesting to a minimum in your translation files.

Please let me know if there are any further details I can provide!