VirtualizedList- inefficient function passing for CellRenderer

• Review the documentation
• Search for existing issues
• Use the latest React Native release - using version 0.55.2 did not see any changes to the FlatListComponent since that version.

Environment

Run react-native info in your terminal and paste its contents here.

Environment:
  OS: Windows 10
  Node: 8.11.1
  Yarn: 0.21.3
  npm: 5.8.0
  Watchman: Not Found
  Xcode: N/A
  Android Studio: Version  3.0.0.0 AI-171.4408382

Packages: (wanted => installed)
  react: 16.3.1 => 16.3.1
  react-native: ^0.55.2 => 0.55.4

Description

I used the npm package why-did-you-update to help optimize my components and prevent re-renders. However there is a re-render that I cannot control. This happens for every item in the list. My gues

CellRenderer.props: Changes are in functions only. Possibly avoidable re-render?
Functions before: {onLayout: ƒ}
Functions after: {onLayout: ƒ}

It seems this is caused by an anonymous function at https://github.com/facebook/react-native/blob/d756d94b3a7e2812f17f549c57767ac63734b49c/Libraries/Lists/VirtualizedList.js#L691

I propose that this function be defined on the class to prevent unnecessary re-renders.

El callback reportado está en Libraries/Lists/VirtualizedList.js, en la línea enlazada. Empieza allí y usa why-did-you-update con el caso descrito de FlatList y CellRenderer para verificar si se puede evitar el rerenderizado causado únicamente por la función. Se considera terminado cuando el callback deja de causar esos rerenderizados innecesarios de CellRenderer sin cambiar el comportamiento de la lista.