Lazy initialization in Ruby

Thu, 16 Jul 2026 08:18:52 +0000

If you’ve been working with Ruby for a while, you’ve probably come across lazy initialization in your projects (it’s actually one of my favorite techniques in Ruby). In most cases, this is a single-line call using the ||= operator, for example: @value ||= some_method. But what if you have a sequence of code that needs to run just once to compute and return the final value? In that case, you can wrap that logic in a begin…end block. Also, don’t forget that if the return value can be nil or false, a simple ||= will re-evaluate on every single call. To handle this, you need to add a guard clause using defined?. And of course, you can always use one of the dedicated gems for this: memoist, memoizable, or memo_wise.

Performance on Artem Yegorov

Lazy initialization in Ruby