EMOM Timer

A high-performance EMOM (Every Minute On the Minute) workout timer with liquid glass aesthetics, built entirely in Rust and WebAssembly.

🌐 Try it live →

�� Rust Documentation →

Features

🎯 Full-Featured Workout Timer

• Precise EMOM timing with visual and color cues
• Customizable rounds and intervals
• Beautiful liquid glass UI with animated wavy cloud effects
• Responsive design optimized for all devices
• Zero drift - maintains accuracy over long sessions

📚 Reusable Countdown Timer Library

• Drift-correcting algorithm - syncs with wall clock to prevent timing errors
• Framework agnostic - works with Yew, Leptos, Dioxus, or vanilla WASM
• Production-ready - extensively tested with comprehensive test suite
• Easy to integrate - simple API with sensible defaults

Why This Timer?

Traditional JavaScript timers (setInterval, setTimeout) suffer from significant drift, especially in:

• Background tabs where browsers throttle to 1Hz
• High CPU load situations that delay callbacks
• Power-saving modes that affect timing precision

The emom countdown timer solves these problems by:

1. Using recursive Timeout calls for flexibility
2. Tracking expected tick time against wall clock
3. Periodically syncing and correcting drift
4. Adjusting when drift exceeds configurable thresholds

Result: Accurate timing that stays precise over minutes or hours, even under adverse conditions.

Quick Start

Use the Web App

Visit the live deployment: http://emom-timer-us-east-2-504242000181.s3-website.us-east-2.amazonaws.com

Run Locally with Docker

The easiest way to run locally is using the provided dev container:

1. Open in VS Code: Reopen in Container
2. Build: trunk build --release
3. Serve: trunk serve --address=0.0.0.0 --release
4. Open your browser to http://localhost:8080

Using the Countdown Timer Library

Add to your Cargo.toml:

[dependencies]
emom = { git = "https://github.com/jac18281828/emomtimer" }

Basic Example

use emom::countdown_timer::{CountdownTimer, TimerConfig};

let config = TimerConfig::default(); // 100ms ticks
let timer = CountdownTimer::new(config, |ticks| {
    println!("Elapsed: {} tenths of a second", ticks);
});

timer.start();
// ... later ...
timer.stop();

Countdown from Duration

use emom::countdown_timer::{CountdownTimer, TimerConfig};
use std::cell::RefCell;
use std::rc::Rc;

let remaining = Rc::new(RefCell::new(600)); // 60 seconds in tenths

let remaining_clone = Rc::clone(&remaining);
let timer = CountdownTimer::new(TimerConfig::default(), move |_ticks| {
    let mut rem = remaining_clone.borrow_mut();
    if *rem > 0 {
        *rem -= 1;
        println!("Remaining: {}.{} seconds", *rem / 10, *rem % 10);
    }
});

timer.start();

Integration with Yew

use yew::prelude::*;
use emom::countdown_timer::{CountdownTimer, TimerConfig};
use std::rc::Rc;

#[function_component]
fn TimerComponent() -> Html {
    let ticks = use_state(|| 0);
    
    let timer = use_memo(|_| {
        let ticks = ticks.clone();
        CountdownTimer::new(TimerConfig::default(), move |t| {
            ticks.set(t);
        })
    }, ());
    
    let start = {
        let timer = Rc::clone(&timer);
        Callback::from(move |_| timer.start())
    };
    
    let stop = {
        let timer = Rc::clone(&timer);
        Callback::from(move |_| timer.stop())
    };
    
    html! {
        <div>
            <p>{ format!("Ticks: {}", *ticks) }</p>
            <button onclick={start}>{"Start"}</button>
            <button onclick={stop}>{"Stop"}</button>
        </div>
    }
}

Configuration

Customize the timer behavior:

use emom::countdown_timer::TimerConfig;

let config = TimerConfig {
    interval_ms: 100,           // Tick every 100ms
    sync_interval_ticks: 10,    // Sync with wall clock every 10 ticks (1 second)
    sync_threshold_ticks: 1,    // Correct if drift exceeds 1 tick (100ms)
};

Configuration Guidelines:

• interval_ms: Tick interval in milliseconds. Use 100 for tenths of seconds, 1000 for full seconds
• sync_interval_ticks: How often to check for drift. Every 10 ticks (1 second) is recommended
• sync_threshold_ticks: Minimum drift before correction. Set to 1 to prevent micro-corrections

See LIBRARY_USAGE.md for detailed examples and advanced usage patterns.

Technology Stack

Built with modern Rust tooling and frameworks:

• Rust - Systems programming language ensuring memory safety and performance
• Yew - Modern Rust framework for building WebAssembly web applications
• WebAssembly - Near-native performance in the browser
• Trunk - WASM web application bundler
• gloo-timers - Thin Rust wrapper over browser timing APIs

Why Yew and WebAssembly?

Yew is a modern Rust framework comparable to React or Vue.js, but with unique advantages:

1. WebAssembly Performance: Compiles to WASM for near-native execution speed
2. Component-Based Architecture: Build complex UIs with reusable, isolated components
3. Memory Safety: Leverage Rust's guarantees to eliminate memory leaks and data races
4. Strong Type System: Catch errors at compile time, not runtime
5. Virtual DOM: Efficient rendering with minimal DOM updates
6. Declarative UI: Clear, readable code with macro-based JSX-like syntax
7. JavaScript Interoperability: Use existing JS libraries when needed
8. Rich Tooling: Cargo for package management, excellent IDE support

Perfect for: Applications where performance, reliability, and type safety are critical.

Development

Prerequisites

• Docker (for dev container)
• OR: Rust 1.70+, trunk, wasm-bindgen

Building

# Development build
trunk build

# Release build with optimizations
trunk build --release

Testing

# Run all tests
cargo test

# Run with coverage
cargo test --all-features

# Lint and format
cargo fmt --check
cargo clippy --all-features --no-deps -- -D warnings

Project Structure

emomtimer/
├── src/
│   ├── lib.rs              # Library exports and countdown timer
│   ├── main.rs             # Yew application and UI
│   └── countdown_timer.rs  # Drift-correcting timer implementation
├── style.css               # Liquid glass UI styling
├── index.html              # Application shell
├── Cargo.toml              # Dependencies and package metadata
└── README.md               # This file

Contributing

Contributions are welcome! Please:

1. Fork the repository
2. Create a feature branch
3. Make your changes with tests
4. Ensure cargo test and cargo clippy pass
5. Submit a pull request

License

This project is open source. See the repository for license details.

Acknowledgments

Built with ❤️ using Rust and WebAssembly. Special thanks to the Yew and Rust communities for excellent tooling and documentation.

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