• animation system: LayoutAnimation: not much control, good for basic animation such as straight from top to bottom animation Animated: for more controls and complicated animations

• 3 basic questions before animating any object: where is the item on the screen at any given time? where is the element moving to ? which element are we moving ?

• import {Animated} from 'react-native'; Animated.Values.Animated >> javascript object that helps us find where the item is on the screen Animated.Types.Spring >> will help us to see how the element is changing it's position or color Animated.Components.View >> what element are we animating

  Animated.timing >> has a linear animation view; just get there Animated.spring >> has a bouncy feeling

-default props in react functional component: [function name].defaultProps = { .... }

in class component: static defaultProps={ .... }

-UIManager

• User Authentication app NEVER: user requests otp >> send device the token in http response >> text user the code (compare codes on user's device ) --- never do the token comparison on device level -- XXXXXX

  BETTER TO DO: user requests OTP >> Acknowledge request >> generate code, save code on backend (using firebase) >> text user a code (twilio) >> user send us correct code >> compare codes on the server >> send user a JWT(json web token) to identify them (firebase)