react-i18next/dist/es/useTranslation.js

Internationalization for react done right. Using the i18next i18n ecosystem.

import { useContext, useCallback, useMemo, useEffect, useRef, useState } from 'react';
import { useSyncExternalStore } from 'use-sync-external-store/shim';
import { getI18n, getDefaults, ReportNamespaces, I18nContext } from './context.js';
import { warnOnce, loadNamespaces, loadLanguages, hasLoadedNamespace, isString, isObject } from './utils.js';
const notReadyT = (k, optsOrDefaultValue) => {
  if (isString(optsOrDefaultValue)) return optsOrDefaultValue;
  if (isObject(optsOrDefaultValue) && isString(optsOrDefaultValue.defaultValue)) return optsOrDefaultValue.defaultValue;
  return Array.isArray(k) ? k[k.length - 1] : k;
};
const notReadySnapshot = {
  t: notReadyT,
  ready: false
};
const dummySubscribe = () => () => {};
export const useTranslation = (ns, props = {}) => {
  const {
    i18n: i18nFromProps
  } = props;
  const {
    i18n: i18nFromContext,
    defaultNS: defaultNSFromContext
  } = useContext(I18nContext) || {};
  const i18n = i18nFromProps || i18nFromContext || getI18n();
  if (i18n && !i18n.reportNamespaces) i18n.reportNamespaces = new ReportNamespaces();
  if (!i18n) {
    warnOnce(i18n, 'NO_I18NEXT_INSTANCE', 'useTranslation: You will need to pass in an i18next instance by using initReactI18next');
  }
  const i18nOptions = useMemo(() => ({
    ...getDefaults(),
    ...i18n?.options?.react,
    ...props
  }), [i18n, props]);
  const {
    useSuspense,
    keyPrefix
  } = i18nOptions;
  const nsOrContext = ns || defaultNSFromContext || i18n?.options?.defaultNS;
  const unstableNamespaces = isString(nsOrContext) ? [nsOrContext] : nsOrContext || ['translation'];
  const namespaces = useMemo(() => unstableNamespaces, unstableNamespaces);
  i18n?.reportNamespaces?.addUsedNamespaces?.(namespaces);
  const revisionRef = useRef(0);
  const subscribe = useCallback(callback => {
    if (!i18n) return dummySubscribe;
    const {
      bindI18n,
      bindI18nStore
    } = i18nOptions;
    const wrappedCallback = () => {
      revisionRef.current += 1;
      callback();
    };
    if (bindI18n) i18n.on(bindI18n, wrappedCallback);
    if (bindI18nStore) i18n.store.on(bindI18nStore, wrappedCallback);
    return () => {
      if (bindI18n) bindI18n.split(' ').forEach(e => i18n.off(e, wrappedCallback));
      if (bindI18nStore) bindI18nStore.split(' ').forEach(e => i18n.store.off(e, wrappedCallback));
    };
  }, [i18n, i18nOptions]);
  const snapshotRef = useRef();
  const getSnapshot = useCallback(() => {
    if (!i18n) {
      return notReadySnapshot;
    }
    const calculatedReady = !!(i18n.isInitialized || i18n.initializedStoreOnce) && namespaces.every(n => hasLoadedNamespace(n, i18n, i18nOptions));
    const currentLng = props.lng || i18n.language;
    const currentRevision = revisionRef.current;
    const lastSnapshot = snapshotRef.current;
    if (lastSnapshot && lastSnapshot.ready === calculatedReady && lastSnapshot.lng === currentLng && lastSnapshot.keyPrefix === keyPrefix && lastSnapshot.revision === currentRevision) {
      return lastSnapshot;
    }
    const calculatedT = i18n.getFixedT(currentLng, i18nOptions.nsMode === 'fallback' ? namespaces : namespaces[0], keyPrefix);
    const newSnapshot = {
      t: calculatedT,
      ready: calculatedReady,
      lng: currentLng,
      keyPrefix,
      revision: currentRevision
    };
    snapshotRef.current = newSnapshot;
    return newSnapshot;
  }, [i18n, namespaces, keyPrefix, i18nOptions, props.lng]);
  const [loadCount, setLoadCount] = useState(0);
  const {
    t,
    ready
  } = useSyncExternalStore(subscribe, getSnapshot, getSnapshot);
  useEffect(() => {
    if (i18n && !ready && !useSuspense) {
      const onLoaded = () => setLoadCount(c => c + 1);
      if (props.lng) {
        loadLanguages(i18n, props.lng, namespaces, onLoaded);
      } else {
        loadNamespaces(i18n, namespaces, onLoaded);
      }
    }
  }, [i18n, props.lng, namespaces, ready, useSuspense, loadCount]);
  const finalI18n = i18n || {};
  const wrapperRef = useRef(null);
  const wrapperLangRef = useRef();
  const createI18nWrapper = original => {
    const descriptors = Object.getOwnPropertyDescriptors(original);
    if (descriptors.__original) delete descriptors.__original;
    const wrapper = Object.create(Object.getPrototypeOf(original), descriptors);
    if (!Object.prototype.hasOwnProperty.call(wrapper, '__original')) {
      try {
        Object.defineProperty(wrapper, '__original', {
          value: original,
          writable: false,
          enumerable: false,
          configurable: false
        });
      } catch (_) {}
    }
    return wrapper;
  };
  const ret = useMemo(() => {
    const original = finalI18n;
    const lang = original?.language;
    let i18nWrapper = original;
    if (original) {
      if (wrapperRef.current && wrapperRef.current.__original === original) {
        if (wrapperLangRef.current !== lang) {
          i18nWrapper = createI18nWrapper(original);
          wrapperRef.current = i18nWrapper;
          wrapperLangRef.current = lang;
        } else {
          i18nWrapper = wrapperRef.current;
        }
      } else {
        i18nWrapper = createI18nWrapper(original);
        wrapperRef.current = i18nWrapper;
        wrapperLangRef.current = lang;
      }
    }
    const arr = [t, i18nWrapper, ready];
    arr.t = t;
    arr.i18n = i18nWrapper;
    arr.ready = ready;
    return arr;
  }, [t, finalI18n, ready, finalI18n.resolvedLanguage, finalI18n.language, finalI18n.languages]);
  if (i18n && useSuspense && !ready) {
    throw new Promise(resolve => {
      const onLoaded = () => resolve();
      if (props.lng) {
        loadLanguages(i18n, props.lng, namespaces, onLoaded);
      } else {
        loadNamespaces(i18n, namespaces, onLoaded);
      }
    });
  }
  return ret;
};