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Web3Auth Integration for Next.js

Web3Auth is a pluggable auth infrastructure for Web3 wallets and applications. This guide will help you integrate Web3Auth into your Next.js application for seamless Web3 authentication.

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Installation

To use Web3Auth in your project, you’ll need to install the following packages: 
npm install @web3auth/modal @web3auth/base @web3auth/openlogin-adapter

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Basic Setup

Create a new file called Web3AuthProvider.tsx in your project:
Web3AuthProvider.tsx
"use client";
import { Web3Auth } from "@web3auth/modal";
import { OpenloginAdapter } from "@web3auth/openlogin-adapter";
import { CHAIN_NAMESPACES } from "@web3auth/base";
import { createContext, useContext, useEffect, useState, ReactNode } from "react";

const Web3AuthContext = createContext<{ web3auth: Web3Auth | null }>({ web3auth: null });

export const useWeb3Auth = () => useContext(Web3AuthContext);

export const Web3AuthProvider = ({ children }: { children: ReactNode }) => {
  const [web3auth, setWeb3auth] = useState<Web3Auth | null>(null);

  useEffect(() => {
    const init = async () => {
      try {
        const web3auth = new Web3Auth({
          clientId: process.env.NEXT_PUBLIC_WEB3AUTH_CLIENT_ID!,
          web3AuthNetwork: "testnet",
          chainConfig: {
            chainNamespace: CHAIN_NAMESPACES.EIP155,
            chainId: "0x1",
            rpcTarget: "https://rpc.ankr.com/eth",
          },
        });

        const openloginAdapter = new OpenloginAdapter({
          adapterSettings: {
            network: "testnet",
            uxMode: "popup",
          },
        });
        web3auth.configureAdapter(openloginAdapter);

        setWeb3auth(web3auth);
        await web3auth.initModal();
      } catch (error) {
        console.error(error);
      }
    };

    init();
  }, []);

  return (
    <Web3AuthContext.Provider value={{ web3auth }}>
      {children}
    </Web3AuthContext.Provider>
  );
};

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Usage

Wrap your app with the Web3AuthProvider in your app/layout.tsx file:
layout.tsx
import { Web3AuthProvider } from '../components/Web3AuthProvider';

export default function RootLayout({
  children,
}: {
  children: React.ReactNode
}) {
  return (
    <html lang="en">
      <body>
        <Web3AuthProvider>
          {children}
        </Web3AuthProvider>
      </body>
    </html>
  )
}

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Now you can use Web3Auth in your components. Here’s an example of a login button:

"use client";
import { useWeb3Auth } from '../components/Web3AuthProvider';
import { useState, useEffect } from 'react';

export default function LoginButton() {
  const { web3auth } = useWeb3Auth();
  const [loggedIn, setLoggedIn] = useState(false);

  useEffect(() => {
    if (web3auth) {
      setLoggedIn(web3auth.connected);
    }
  }, [web3auth]);

  const login = async () => {
    if (!web3auth) {
      console.log("web3auth not initialized yet");
      return;
    }
    const web3authProvider = await web3auth.connect();
    setLoggedIn(true);
  };

  const logout = async () => {
    if (!web3auth) {
      console.log("web3auth not initialized yet");
      return;
    }
    await web3auth.logout();
    setLoggedIn(false);
  };

  if (!web3auth) {
    return <div>Loading...</div>;
  }

  if (loggedIn) {
    return <button onClick={logout}>Log Out</button>;
  }

  return <button onClick={login}>Login with Web3Auth</button>;
}