📦 once

once ensures a function is executed only once. Subsequent calls return the value from the initial invocation. It's useful for initialization routines or callbacks that should only run a single time, preventing unintended side effects or redundant operations. This lightweight, dependency-free utility promotes cleaner, more predictable code execution, especially in asynchronous environments where callbacks might be triggered multiple times erroneously. Simple but powerful, once enhances code reliability and maintainability.