GitHub Lookup

A GitHub user lookup TUI demonstrating the async/effects pattern.

Demonstrates:

• Effect-based async with Did* action pattern
• TaskManager for HTTP request cancellation
• Loading states and error handling
• Text input handling

Running

cargo run -p github-lookup-example

Type a GitHub username and press Enter to fetch user info. Press Esc to clear, Ctrl+C to quit.

Key Pattern

This example shows the recommended async flow:

1. User types username, presses Enter
2. Action::UserFetch(username) dispatched
3. Reducer sets is_loading = true and returns Effect::FetchUser
4. Effect handler spawns task via ctx.tasks().spawn()
5. Task completes and sends Action::UserDidLoad or Action::UserDidError
6. Reducer updates state, UI re-renders

// Intent action triggers async work
Action::UserFetch(username) => {
    state.is_loading = true;
    DispatchResult::changed_with(Effect::FetchUser { username })
}

// Result action updates state
Action::UserDidLoad(user) => {
    state.user = Some(user);
    state.is_loading = false;
    DispatchResult::changed()
}

This is the same pattern taught in the async-fetch tutorial, which walks through building this example from scratch.

Source Structure

examples/github-lookup/
├── src/
│   ├── main.rs      # Terminal setup, EffectRuntime
│   ├── state.rs     # AppState, GitHubUser
│   ├── action.rs    # Action enum (intent + result)
│   ├── effect.rs    # Effect::FetchUser
│   ├── reducer.rs   # State mutations
│   ├── api.rs       # GitHub API client
│   └── ui.rs        # Rendering + key handling
└── Cargo.toml