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ML SystemPart 1: Core ConceptsChapter 5
CH.05 ~30 min

State Management

useState, Props, and Data Flow.

useStatePropsData Flow
  • Manage simple and complex state using the useState hook.
  • Pass data and callback functions between components using props.
  • Identify when to lift state up in a component hierarchy.

01 Internal State & Hooks Viz

Definition

useState

A hook that allows functional components to have their own state. It returns a pair: the current state value and a function to update it.

Asynchronous Updates

State updates in React are asynchronous. Calling a setter function does not immediately change the value in the current execution block but schedules a re-render.

02 Unidirectional Data Flow

Definition

Lifting State Up

A pattern where state is moved to the closest common ancestor of components that need it, making the ancestor the 'single source of truth'.

Key Takeaways

  1. 1useState is the primary tool for managing dynamic data in functional components.
  2. 2State updates are scheduled and asynchronous, not immediate.
  3. 3Lifting state up ensures that multiple components stay in sync with the same data.

CH.05

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