Way of thinking: 1) We need a recursive function to calculate multiply of **ordered** numbers. 2) We must return 1 when we get 0 and we must stop recursive function.

In JavaScript, we declare variables with CONST when we want to protect it from mutation. But CONST declaration alone is not enough to protect really.

While developing SPA project, we sometimes need to use API keys. Although it is possible to hide these API keys with **.ENV file importing** method, you must find another method on production process because of the fact that....