Discuss desired behavior of rerender

[shaman-apprentice]

Current behavior of rerender

It destroys old component and creates a new one from scratch with given properties.

My thoughts on it

• Name rerender does not suggest to me, that component is created from scratch nor old one is destroyed.
• Angular-testing-library should behave similar to react-testing-library. React's version of rerender does keep existing instance, meaning constructor of class and componentDidMount will not be called. render and componentDidUpdate will get called. Therefore I think rerender should not create the component from scratch but call ngOnChanges with simpleChange parameter containing previous values. Not passed in properties should be removed.
• rerender seems to update props instead of replacing them #252 should work with rerender

When the component in rerender is not created from scratch, I think change is not useful anymore. All properties are controlled from outside. So we can pass in all properties we want to keep in rerender unmodified again. I guess that's why React's API doesn't have an equivalent of change.

[timdeschryver]

Do you want to create a PR for this change @shaman-apprentice ?
I do agree that it should behave the same as the other testing libraries.