The Hollywood Principle refers to the often repeated phrase in pop-culture "Don't call us, we'll call you"

There are a huge amount of applications to this rule as it's quite general, but the often cited example is:

In any framework/library there are certain function that you shouldn't call yourself.

In React for example, you don't need to ever call componentDidMount() as it will be called for you.

At the end of the constructor you don't need to work out how to call this function, it will be called for you, componentDidMount is saying "Don't call me, I will call you when I'm ready."

This is true for so many other frameworks/libraries

• In Angular, you don't need to call ngOnDestroy() it will be called for you in the lifecyle
• In Vue, you don't need to call beforeCreate() it will be called for you in the lifecyle

By having these life-cycle methods that get called for you at pre-determined times, the schedule and flow of your app is simplified significantly.