Throwing and asynchronous Swift properties
Swift 5.5 introduces a new concept called “effectful read-only properties”, which essentially means that computed properties can now utilize control flow mechanisms like errors and async operations when computing their values.
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Let’s start by taking a look at how computed properties can now throw errors using Swift’s standard error handling mechanism. As an example, let’s say that we’re currently using the built-in Result type’s get method to either extract a result’s wrapped value, or throw any error that it contains:
Since that get method doesn’t actually perform any kind of work, but rather just lets us unpack a Result value using the try keyword, it could now just as well be declared as a property — for example like this:
