【React/Next.js】遷移元のURLを取得する方法！

import { createContext } from 'react';

export const HistoryContext = createContext<string[]>(['', '']);

import { useEffect, useState } from 'react';
import { HistoryContext } from 'hooks';
import type { AppProps } from 'next/app';
import { useRouter } from 'next/router';

const App = ({ Component, pageProps }: AppProps) => {
  const router = useRouter();
  const [history, setHistory] = useState([router.asPath, '']);

  useEffect(() => {
    setHistory([router.asPath, history[0]]);
  }, [router.asPath]);

  return (
    <HistoryContext.Provider value={history}>
      <UnchiComponent />
    </HistoryContext.Provider>
  );
};

export default App;

import { useContext, useEffect } from 'react';
import { HistoryContext } from 'hooks/historyContext';

export const UnchiComponent = () => {
  const history = useContext(HistoryContext);

  useEffect(() => {
    // 遷移元URLのパスが「/unchi/」の場合
    if (history[0] === '/unchi/') {
      console.log('うんち爆弾！！！')
    }
  }, []);

  return (
    <></>
  )
};