Modern Full-Stack Development

 A Worker for All Seasons
Just like the server side of MailBag, we have three “Worker” classes on the client 
side: Contacts.ts, IMAP.ts, and SMTP.ts. These are the interface between the client 
application itself and the MailBag server, and they break down functionally in the same 
way as their server counterparts. Before we look at the React code itself that defines out 
Chapter 9   Delivering the gooDs: MailBag, the Client

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UI and makes it functional, let’s take a look at these Worker classes so that when you see 
them being used, you’ll know what they’re doing.
But how, exactly, does the code in these workers talk to the server? For that, we must 
take a quick detour!