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| //Marking vars with the "lazy" keyword will make it so they are only initialized if called, and only initialized once.
lazy var dateFormatter = DateFormatter()
//One cool feature of Swift a lot of people don't realize is that constants work the same way!! The following object will only be initialized if/when it gets called. It's even thread-safe. Warning: it will stay in memory unless you manually manage it or it gets dereferenced. Be extra cautious if it is global.
static let someBigAsset = MegaClass()
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Other tips
To add onto this, you can use the @autoclosure closure keyword instead of @escaping to give lazy-like tendencies to your closures. Auto closure means the closure won’t initialize or execute until it’s called, so it saves execution time.
— Josh Jaslow
Originally published 09/23/2021 https://pittcsc.org/, republished 09/09/2022.