React-08: state of the three core attributes of component instances

Accurately distinguish between simple components and complex components

• Simple component without state
• Complex components have state

Initialize state

• Modify in the constructor of the component class
• First pass the parameter props to the constructor, this parameter is automatically passed to us by React.
• Call super()
• Initialize state
• Here this refers to the instance object of the component
  

General shorthand for state