How to use the shopify-buy.buildClient function in shopify-buy

import React from 'react';
import ReactDOM from 'react-dom';
import './index.css';
import App from './App';
import * as serviceWorker from './serviceWorker';
import Client from 'shopify-buy';
import { Provider } from 'react-redux';
import store from './store';
import './styles/shopify.css';

// build shopify client
const client = Client.buildClient({
    storefrontAccessToken: 'YOUR_SHOPIFY_STOREFRONT_ACCESS_TOKEN',
    domain: 'YOUR_MYSHOPIFY_STORE_URL'
});
store.dispatch({type: 'CLIENT_CREATED', payload: client});

// buildClient() is synchronous, so we can call all these after!
client.product.fetchAll().then((res) => {
  store.dispatch({type: 'PRODUCTS_FOUND', payload: res});
});
client.checkout.create().then((res) => {
  store.dispatch({type: 'CHECKOUT_FOUND', payload: res});
});
client.shop.fetchInfo().then((res) => {
  store.dispatch({type: 'SHOP_FOUND', payload: res});
});

import React from 'react';
import ReactDOM from 'react-dom';
import App from './App';
import Client from 'shopify-buy';
import '../../shared/app.css';

const client = Client.buildClient({
  storefrontAccessToken: 'dd4d4dc146542ba7763305d71d1b3d38',
  domain: 'graphql.myshopify.com'
});

ReactDOM.render(
  ,
  document.getElementById('root')
);

import React from 'react'
import Client from 'shopify-buy'

const client = Client.buildClient({
  storefrontAccessToken: process.env.SHOPIFY_ACCESS_TOKEN,
  domain: `${process.env.SHOP_NAME}.myshopify.com`,
})

export const defaultStoreContext = {
  client,
  adding: true,
  checkout: { lineItems: [] },
  products: [],
  shop: {},
  filteredType: 'all',
  filteredSort: 'featured',
  addVariantToCart: () => { },
  addVariantToCartAndBuyNow: () => { },
  removeLineItem: () => { },
  updateLineItem: () => { },

import fetch from 'node-fetch';
import Client from 'shopify-buy';

global.fetch = fetch;

const client = Client.buildClient({
  storefrontAccessToken: '20ef0127c6c37cee73dd149879a379a8',
  domain: 'faheemnusrat.com'
});

export default client;

import React, { useState, useEffect } from 'react'
import Client from 'shopify-buy'

import Context from '~/context/StoreContext'

const client = Client.buildClient({
  storefrontAccessToken: process.env.SHOPIFY_ACCESS_TOKEN,
  domain: `${process.env.SHOP_NAME}.myshopify.com`,
})

const ContextProvider = ({ children }) => {
  let initialStoreState = {
    client,
    adding: false,
    checkout: { lineItems: [] },
    products: [],
    shop: {},
  }

  const [store, updateStore] = useState(initialStoreState)

  useEffect(() => {

import React from 'react';
import Client from 'shopify-buy';

const client = Client.buildClient({
  domain: 'gatsby-swag.myshopify.com',
  storefrontAccessToken: '9aa73c089d34741f36edbe4d7314373a'
});

export const defaultStoreContext = {
  client,
  isCartOpen: false,
  checkout: { lineItems: [] },
  products: [],
  shop: {},
  addVariantToCart: () => {},
  removeLineItem: () => {},
  updateLineItem: () => {},
  toggleCart: () => {}
};

import React from 'react'
import PropTypes from 'prop-types'
import Helmet from 'react-helmet'
import Client from 'shopify-buy'

import Header from '../components/header'
import './index.css'

const shopifyClient = Client.buildClient({
  domain: `${process.env.GATSBY_SHOPIFY_SHOP_NAME}.myshopify.com`,
  storefrontAccessToken: process.env.GATSBY_SHOPIFY_ACCESS_TOKEN,
})

const Layout = ({ children, data, ...props }) => (
  <div>
    
    <header>
    </header></div>

import React from 'react'
import Client from 'shopify-buy'

const client = Client.buildClient({
  domain: `${process.env.SHOPIFY_STORE_NAME}.myshopify.com`,
  storefrontAccessToken: process.env.SHOPIFY_SECRET,
})

export const defaultStoreContext = {
  client,
  adding: false,
  checkout: { lineItems: [] },
  products: [],
  shop: {},
  filteredType: 'all',
  addVariantToCart: () => {},
  removeLineItem: () => {},
  updateLineItem: () => {},
}