State management has become a common challenge when developing web applications.

The time when we directly changed the UI for display data is long gone. All major UI libraries come with a new approach, changing the UI means actually changing the state.

This book gives you an overview of how state is managed by building a note-taking application with four different libraries. We start from an object-oriented approach using Svelte, centralize state with Vuex, then move to a functional approach with React and Redux, and in the end arrive at a solution using only pure functions with Elm.

Here are some of the things we will go through:

• Understand what state is
• Recognize domain and UI state
• Encapsulate state inside stores with Svelte
• Centralize state management with Vuex
• Learn the Flux architecture
• Apply functional principles in state management with Redux
• Handle side-effects with Redux Thunk
• Manage state using only pure functions with Elm