Props and Data Flow

What Are Props?

Props are read-only data passed from parent to child - the configuration of a component.

Default Props and Validation

Provide fallbacks with default parameters and validate with PropTypes in development.

function Greeting({ name = 'Guest' }) {
  return <h1>Hello, {name}</h1>;
}

Props vs State

• Props - from parent, read-only.
• State - local, mutable via setter.

Key Points

• Data flows down; events flow up.
• Never mutate props inside a child.
• Deep drilling signals a need for Context.