Learn ELM with Real Code Examples
Updated Nov 20, 2025
Architecture
The Elm Architecture (TEA) with Model, Update, and View functions
Immutable data flow
One-way data binding
Subscriptions for side effects
Module-based project structure
Rendering Model
Elm code compiled to JavaScript
Model state flows through Update function
View function renders virtual DOM
Commands and Subscriptions handle side effects
Browser updates DOM efficiently
Architectural Patterns
The Elm Architecture (Model, Update, View)
Pure functions drive program behavior
One-way data flow
Encapsulation via modules
Subscriptions for event-driven programming
Real World Architectures
Single-page applications (SPA)
Interactive dashboards and charts
Real-time communication apps
Form-heavy applications
Games using Elm graphics library
Design Principles
Pure functional programming
Immutable data by default
Type safety and no runtime exceptions
Simplicity and maintainability
Predictable and structured architecture (TEA)
Scalability Guide
Organize large apps into modules
Use Msg and Update hierarchies for large state trees
Batch Cmds for efficiency
Optimize subscriptions
Compile with optimizations for production
Migration Guide
Port Elm 0.18 projects to Elm 0.19
Update TEA patterns to current syntax
Replace deprecated modules with core Elm packages
Refactor ports for JS interop
Ensure type-safe conversions