strategy-client.js

const ReceiptManager = require('./receipt-manager');
const {
    EmailStrategy,
    SlackStrategy,
} = require('./strategy');
 
function main(orderId, userEmail) {
    const manager = new ReceiptManager();
 
    const email = new EmailStrategy();
    manager.sendReceipt(orderId, userEmail, email);
 
    const slack = new SlackStrategy();
    manager.sendReceipt(orderId, userEmail, slack);
}