botframework-node-sdk-welcome-message.js

// Welcome message for Node.js bot
bot.on('conversationUpdate', function (message) {
    if (message.membersAdded) {
        message.membersAdded.forEach(function (identity) {
            if (identity.id == message.address.bot.id) {
                // Bot is joining conversation
                // - For WebChat channel you'll get this on page load.
                var reply = new builder.Message()
                        .address(message.address)
                        .text("Welcome to my page");
                bot.send(reply);
            } else {
                // User is joining conversation
                // - For WebChat channel this will be sent when user sends first message.
                // - When a user joins a conversation the address.user field is often for
                //   essentially a system account so to ensure we're targeting the right 
                //   user we can tweek the address object to reference the joining user.
                // - If we wanted to send a private message to teh joining user we could
                //   delete the address.conversation field from the cloned address.
                var address = Object.create(message.address);
                address.user = identity;
                var reply = new builder.Message()
                        .address(address)
                        .text("Hello %s", identity.name);
                bot.send(reply);
            }
        });
    }
});