fair-rose•2w ago

i18n provider doesn't match the types from i18next

The type that refine expects in the I18nProvider, the translate key doesn't match the type of the 18next t function. Getting the following error:

Type '(key: string, options?: any, defaultMessage?: string) => string | $SpecialObject | TFunctionDetailedResult<string | $SpecialObject, any>' is not assignable to type 'TranslateFunction'.
  Type 'string | $SpecialObject | TFunctionDetailedResult<string | $SpecialObject, any>' is not assignable to type 'string'.
    Type 'object' is not assignable to type 'string'.ts(2322)
types.d.ts(5, 5): The expected type comes from property 'translate' which is declared here on type 'I18nProvider'
    Type 'object' is not assignable to type 'string'.ts(2322)

Type '(key: string, options?: any, defaultMessage?: string) => string | $SpecialObject | TFunctionDetailedResult<string | $SpecialObject, any>' is not assignable to type 'TranslateFunction'.
  Type 'string | $SpecialObject | TFunctionDetailedResult<string | $SpecialObject, any>' is not assignable to type 'string'.
    Type 'object' is not assignable to type 'string'.ts(2322)
types.d.ts(5, 5): The expected type comes from property 'translate' which is declared here on type 'I18nProvider'
    Type 'object' is not assignable to type 'string'.ts(2322)

In this code taken directly from the documentation page:

  const i18nProvider: I18nProvider = {
    translate: (key: string, options?: any, defaultMessage?: string) =>
      t(key, defaultMessage, options),
    changeLocale: (lang: string) => i18n.changeLanguage(lang),
    getLocale: () => i18n.language,
  }

  const i18nProvider: I18nProvider = {
    translate: (key: string, options?: any, defaultMessage?: string) =>
      t(key, defaultMessage, options),
    changeLocale: (lang: string) => i18n.changeLanguage(lang),
    getLocale: () => i18n.language,
  }

5 Replies

kapa.ai•2w ago

Hi @JuicyBenjamin. I'm kapa.ai, your friendly support bot. I will try to answer your question by searching through the knowledge base. :wave: ---------------------- You're right, there seems to be a mismatch between the types expected by refine's I18nProvider and the types returned by i18next's t function. This is a known issue that has been reported in the refine GitHub repository. Let me explain the problem and provide a workaround. The issue arises because refine's I18nProvider expects the translate function to always return a string, while i18next's t function can return different types depending on the configuration and usage. There are a couple of ways to address this: 1. Type assertion (quick workaround): You can use a type assertion to tell TypeScript that the result of the t function will be a string. Here's how you can modify the code:

const i18nProvider: I18nProvider = {
  translate: (key: string, options?: any, defaultMessage?: string) =>
    t(key, defaultMessage, options) as string,
  changeLocale: (lang: string) => i18n.changeLanguage(lang),
  getLocale: () => i18n.language,
};

const i18nProvider: I18nProvider = {
  translate: (key: string, options?: any, defaultMessage?: string) =>
    t(key, defaultMessage, options) as string,
  changeLocale: (lang: string) => i18n.changeLanguage(lang),
  getLocale: () => i18n.language,
};

2. Use the second argument for options: According to the refine documentation on i18n Provider (https://refine.dev/docs/i18n/i18n-provider/#methods), you can pass the options as the second argument. This approach might resolve the type mismatch:

const i18nProvider: I18nProvider = {
  translate: (key: string, options?: any, defaultMessage?: string) =>
    t(key, options),
  changeLocale: (lang: string) => i18n.changeLanguage(lang),
  getLocale: () => i18n.language,
};

const i18nProvider: I18nProvider = {
  translate: (key: string, options?: any, defaultMessage?: string) =>
    t(key, options),
  changeLocale: (lang: string) => i18n.changeLanguage(lang),
  getLocale: () => i18n.language,
};

It's worth noting that this issue has been discussed in the refine GitHub repository. In issue #6313 (https://github.com/refinedev/refine/issues/6313), a user reported a similar problem with the typing for i18next being too rigid. The refine team acknowledged this and mentioned that they were planning to work on allowing customization of the translation key type with module augmentation. As a temporary solution, they suggested passing the array key in an object using the second argument, which aligns with the second approach I mentioned above. If these workarounds don't solve your problem or if you need a more robust solution, you might want to consider creating a custom wrapper for the t function that ensures it always returns a string, or wait for the refine team to implement a more flexible typing system for the i18n provider. ---------------------- Note: you can ask me a follow up question by @ mentioning me again :speech_balloon: ----------------------

kapa.ai•2w ago

<@167296048367140864> Kapa.ai is still learning and improving, please let me know how I did by reacting below.

fair-roseOP•2w ago

@kapa.ai while the type assertion will help the translate key error, I'm stuck with the t type error:

Argument of type '[string, string | undefined, any]' is not assignable to parameter of type '[key: string | TemplateStringsArray | (string | TemplateStringsArray)[], options?: any] | [key: string | string[], options: any] | [key: string | string[], defaultValue: string, options?: any]'.
  Type '[string, string | undefined, any]' is not assignable to type '[key: string | string[], defaultValue: string, options?: any]'.
    Type at position 1 in source is not compatible with type at position 1 in target.
      Type 'string | undefined' is not assignable to type 'string'.
        Type 'undefined' is not assignable to type 'string'.ts(2345)

Argument of type '[string, string | undefined, any]' is not assignable to parameter of type '[key: string | TemplateStringsArray | (string | TemplateStringsArray)[], options?: any] | [key: string | string[], options: any] | [key: string | string[], defaultValue: string, options?: any]'.
  Type '[string, string | undefined, any]' is not assignable to type '[key: string | string[], defaultValue: string, options?: any]'.
    Type at position 1 in source is not compatible with type at position 1 in target.
      Type 'string | undefined' is not assignable to type 'string'.
        Type 'undefined' is not assignable to type 'string'.ts(2345)

kapa.ai•2w ago

Let me check the knowledge base for you again. One moment! :books: ---------------------- The error you're encountering is due to a mismatch in the function signature of the t function from i18next and how it's being called in the translate method of the i18nProvider. Let's address this issue based on the information from the refine documentation. According to the refine documentation on i18n Provider methods (https://refine.dev/docs/i18n/i18n-provider/#methods), the translate function in the i18nProvider should have two function signatures:

function translate(key: string, options?: any, defaultMessage?: string): string;
function translate(key: string, defaultMessage?: string): string;

function translate(key: string, options?: any, defaultMessage?: string): string;
function translate(key: string, defaultMessage?: string): string;

To align with these signatures and resolve the type error, you should modify your i18nProvider implementation as follows:

const i18nProvider: I18nProvider = {
  translate: (key: string, options?: any, defaultMessage?: string) => {
    if (typeof options === 'string') {
      // This is the case where options is actually the defaultMessage
      return t(key, { defaultValue: options });
    }
    // This is the case where options is an object (or undefined)
    return t(key, { ...options, defaultValue: defaultMessage });
  },
  changeLocale: (lang: string) => i18n.changeLanguage(lang),
  getLocale: () => i18n.language,
};

const i18nProvider: I18nProvider = {
  translate: (key: string, options?: any, defaultMessage?: string) => {
    if (typeof options === 'string') {
      // This is the case where options is actually the defaultMessage
      return t(key, { defaultValue: options });
    }
    // This is the case where options is an object (or undefined)
    return t(key, { ...options, defaultValue: defaultMessage });
  },
  changeLocale: (lang: string) => i18n.changeLanguage(lang),
  getLocale: () => i18n.language,
};

This implementation handles both function signatures and correctly passes the parameters to the i18next t function. Here's what it does: 1. If options is a string, it treats it as the defaultMessage and passes it as the defaultValue option to the t function. 2. Otherwise, it spreads the options object (if provided) and adds the defaultMessage as the defaultValue option. This approach should resolve the type error you're encountering while maintaining compatibility with both refine's I18nProvider interface and i18next's t function. Remember to add a type assertion to string if the TypeScript compiler still complains about the return type:

return t(key, { ...options, defaultValue: defaultMessage }) as string;

return t(key, { ...options, defaultValue: defaultMessage }) as string;

This solution is based on the information provided in the refine i18n Provider documentation (https://refine.dev/docs/i18n/i18n-provider/#methods) and should address the type mismatch issues you're experiencing. ---------------------- Note: you can ask me a follow up question by @ mentioning me again :speech_balloon: ----------------------

kapa.ai•2w ago

<@167296048367140864> Kapa.ai is still learning and improving, please let me know how I did by reacting below.