react-i18next on React Native No overload matches this call typescript

Question

Iam trying to configure react-i18next 11.8.2 in my React Native app with typescript 4.1.2:

i18n.use(initReactI18next).init({
  resources: {
    en,
    es,
  },
  lng: 'es',
  fallbackLng: 'es',
  interpolation: {
    escapeValue: false,
  },
});

with two resources files (en, es).

But i am getting an typescript error with the TFunction interface using the useTranslation hook:

const {t, i18n} = useTranslation(['SelectLanguage']);]

<StyledLabel>{t('SelectLanguage:title')}</StyledLabel>

The error:

No overload matches this call.
  Overload 1 of 2, '(props: Pick<Pick<TextProps & RefAttributes<Text>, "key" | "ref" | "style" | "onLayout" | "testID" | "nativeID" | "accessible" | "accessibilityActions" | ... 35 more ... | "dataDetectorType"> & Partial<...>, "key" | ... 42 more ... | "dataDetectorType"> & { ...; } & { ...; } & { ...; }): ReactElement<...>', gave the following error.
    Type 'TFunctionResult' is not assignable to type 'string | number | TextElement | ChildElement[] | (string & {}) | (string & ReactElement<any, string | ((props: any) => ReactElement<any, string | ... | (new (props: any) => Component<any, any, any>)> | null) | (new (props: any) => Component<...>)>) | ... 20 more ... | undefined'.
      Type 'null' is not assignable to type 'string | number | TextElement | ChildElement[] | (string & {}) | (string & ReactElement<any, string | ((props: any) => ReactElement<any, string | ... | (new (props: any) => Component<any, any, any>)> | null) | (new (props: any) => Component<...>)>) | ... 20 more ... | undefined'.
  Overload 2 of 2, '(props: StyledComponentPropsWithAs<typeof Text, any, {}, never>): ReactElement<StyledComponentPropsWithAs<typeof Text, any, {}, never>, string | ... 1 more ... | (new (props: any) => Component<...>)>', gave the following error.
    Type 'TFunctionResult' is not assignable to type 'string | number | TextElement | ChildElement[] | (string & {}) | (string & ReactElement<any, string | ((props: any) => ReactElement<any, string | ... | (new (props: any) => Component<any, any, any>)> | null) | (new (props: any) => Component<...>)>) | ... 20 more ... | undefined'.
      Type 'null' is not assignable to type 'string | number | TextElement | ChildElement[] | (string & {}) | (string & ReactElement<any, string | ((props: any) => ReactElement<any, string | ... | (new (props: any) => Component<any, any, any>)> | null) | (new (props: any) => Component<...>)>) | ... 20 more ... | undefined'.ts(2769)
text.component.d.ts(15, 5): The expected type comes from property 'children' which is declared here on type 'IntrinsicAttributes & Pick<Pick<TextProps & RefAttributes<Text>, "key" | "ref" | "style" | "onLayout" | "testID" | ... 38 more ... | "dataDetectorType"> & Partial<...>, "key" | ... 42 more ... | "dataDetectorType"> & { ...; } & { ...; } & { ...; }'
text.component.d.ts(15, 5): The expected type comes from property 'children' which is declared here on type 'IntrinsicAttributes & Pick<Pick<TextProps & RefAttributes<Text>, "key" | "ref" | "style" | "onLayout" | "testID" | ... 38 more ... | "dataDetectorType"> & Partial<...>, "key" | ... 42 more ... | "dataDetectorType"> & { ...; } & { ...; } & { ...; }'

I can solve this error by parsing the result of the i18n translation like this:

<StyledLabel>{t<string>('SelectLanguage:title')}</StyledLabel>

Do you have any idea of why this is happening? i think it could be the StyledLabel props, it is just an styled component of a @ui-kitten/components Text

import styled from 'styled-components/native';
import {Text} from '@ui-kitten/components';

export const StyledLabel = styled(Text)`
  margin-bottom: 5px;
`;

the text.component of UI Kitten:

export declare class Text extends React.Component<TextProps> {
    render(): React.ReactElement<RNTextProps>;
}
export {};

Answer 1

In my case I was using a ^18 version of the types of React. If your are using React 17, use the correct version:

    "@types/react": "17.0.19",
    "@types/react-dom": "17.0.9",

Answer 2

One other solution is to use withTranslation

import React from "react";
import { Link, Redirect } from "react-router-dom";
import "./Screen.css";
import ImageHolder from "../../../../assets/imageholder.png";
import { withTranslation } from "react-i18next";

export interface Screen3Props {
  t: any;
}

const Screen3: React.FunctionComponent<Screen3Props> = ({ t }: Screen3Props) => {
  const [redirect, setRedirect] = React.useState(false);
  return (
    <div className="ms-welcome initPage">
      <p className="h1">{t("SEARCH_PRIMARY_TEXT")}</p>
      <p className="h2">{t("SEARCH_SECONDARY_TEXT")}</p>
    </div>
  );
};

export default withTranslation()(Screen3);

 

Answer 3

In the error message, you can find the problem.

Type 'TFunctionResult' is not assignable to type 'string | number | TextElement | ChildElement[] | (string & {}) | (string & ReactElement<any, string

TFunctionResult accept only string

Solution: You need to always send a string and refer it as string

<StyledLabel>{t<string>('SelectLanguage:title')}</StyledLabel>

Second solution

<StyledLabel>{`${t('SelectLanguage:title')}`}</StyledLabel>

Answer 4

Create react-i18next.d.ts

import "react-i18next";

import type * as translations from "locales";

declare module "react-i18next" {
  type DefaultResources = typeof translations;
  interface Resources extends DefaultResources {}
}

declare module "react-i18next" {
  type Namespace = keyof typeof translations;
  type Keys<N extends Namespace> = keyof typeof translations[N];

  interface TFunction<
    TResult extends TFunctionResult = string,
    TKeys extends TFunctionKeys = string,
    TInterpolationMap extends object = StringMap
  > {
    // basic usage
    (key: TKeys | TKeys[], options?: TOptions<TInterpolationMap> | string): TResult;
    // overloaded usage
    (key: TKeys | TKeys[], defaultValue?: string, options?: TOptions<TInterpolationMap> | string): TResult;
  }

  type UseTranslationResult<N> = {
    t: TFunction<string, Keys<N>>;
    i18n: i18n;
    ready: boolean;
  };
  export function useTranslation<N extends Namespace>(ns: N, options?: UseTranslationOptions): UseTranslationResult<N>;
}