Gate Classes

Gate classes is a term I've used to name a certain pattern that I use in certain contexts.

At times, you have code where you don't want the rest of the function to run at all unless certain conditions are met (such as guard clauses):

if(!order.wasCancelled()) {
    // A bunch of code that does stuff.
    if(!order.isFraudlent()) {
        // Some more code.
    }
}

Notice that we have two conditionals (one being nested) and they are not followed by else or else if.

They make one check and act as a gate, as it were, to the rest of the code inside that if statement.

That's why I like to call these kinds of statement gates since they only let the rest of the code run if the gate is opened up.

Scenario

Here's the situation we're going to address. It's similar to the code above, but now we have some repositories that are being used to fetch data to conduct our checks:

const accountIsVerified = await accountRepo.accountIsVerified...