Introduction
Elm is a fascinating anomaly in the world of programming languages. While most languages evolve by adding features, Elm has taken the opposite approach—removing unnecessary complexity while maintaining its practicality for large-scale projects. This philosophy has made Elm one of the most stable, predictable, and enjoyable languages to work with. Unlike other languages that continuously introduce new syntax and bloated standard libraries, Elm has remained lean and focused, proving that simplicity is a strength rather than a limitation.
In this post, we’ll explore the history of Elm, its philosophy of feature removal, and how this approach has contributed to its longevity and reliability. We’ll also highlight real-world projects that have successfully used Elm and examine specific features that have been removed from the language and its core libraries.
The Origins and Evolution of Elm
Elm was created by Evan Czaplicki in 2012 as part of his thesis at Harvard University. Initially designed as a functional language for building web applications, Elm quickly gained traction due to its strong type system, immutability, and absence of runtime exceptions. Over the years, Elm has influenced other technologies, including Redux, Rust, Vue, Roc, and Gren.
Elm’s early versions included features that were later removed to streamline the language. Unlike JavaScript, Python, or even Haskell, Elm does not chase trends or introduce unnecessary complexity. Instead, its development has focused on removing features that do not contribute to its core philosophy.
Why Elm Removes Features Instead of Adding Them
Most programming languages evolve by adding more features—syntax enhancements, expanded standard libraries, and new paradigms. Elm takes the opposite approach: features that introduce complexity, unpredictability, or redundancy are eliminated to keep the language simple and practical. Let’s explore some of the most significant removals in Elm’s history.
1. Removal of Native Modules
Earlier versions of Elm allowed developers to write native JavaScript modules to extend functionality. While this was convenient, it violated Elm’s core guarantees of no runtime exceptions and predictable behavior.
Native modules could lead to uncontrolled side effects, making debugging difficult. By removing them, Elm ensured that all code written in Elm remains safe, type-checked, and fully verified by the compiler. This move solidified Elm’s reputation for reliability—if your Elm code compiles, it works.
2. Elimination of Higher-Kinded Types
Functional languages like Haskell rely heavily on higher-kinded types, which allow for abstract structures like monads, functors, and lenses. While these features are powerful, they also introduce steep learning curves and additional complexity.
Elm deliberately avoids higher-kinded types, making its type system intuitive and approachable. The result? Developers can focus on practical application development rather than wrestling with complex abstractions.
3. Standard Library Simplifications
Elm’s standard library has undergone multiple reductions to maintain simplicity and predictability. Some notable removals include:
-
No implicit number-to-string conversions → Instead of allowing automatic type conversion, Elm forces explicit formatting using
String.fromIntorString.fromFloat, making type handling more predictable. - No complex data structures → Elm favors simple lists and records over intricate abstractions like monads or lenses, ensuring that code remains straightforward and readable.
4. No Custom Operators
Unlike many functional languages, Elm does not allow developers to define custom operators. While operators can make code more concise, they often introduce ambiguity—different developers might interpret the same symbols differently.
By enforcing explicit function calls, Elm keeps code clear, maintainable, and beginner-friendly.
5. Removal of Case Guards
Elm previously supported case guards, a feature common in languages like Haskell and OCaml. However, they were removed due to their syntactic complexity and tendency to make pattern matching less predictable.
Instead, Elm encourages explicit conditional logic, making the flow of programs easier to follow and debug.
6. The Removal of Custom Side Effects
Elm’s approach to managing side effects is one of its most defining characteristics. In earlier versions, developers could define custom effects tailored to their application. However, Elm later removed the ability to create arbitrary effects, restricting developers to a predefined set of managed side effects.
This decision wasn’t about limiting power—it was about preserving predictability. Many languages allow developers to introduce uncontrolled side effects, leading to hidden bugs, unexpected interactions, and difficult debugging. Elm avoids these pitfalls by offering a structured effect management system, including:
- HTTP requests
- WebSockets
- Ports (interacting with JavaScript)
- Time-based events
- Randomness
By restricting side effects to only those officially supported by Elm, developers no longer need to worry about unintentional bugs, race conditions, or concurrency issues. Every Elm program follows the same uniform rules, making debugging easier and system behavior entirely predictable.
Successful Projects That Use Elm
Elm’s minimalist approach doesn’t just work in theory—it has been successfully adopted by major companies and large-scale projects:
1. NoRedInk
A leading education platform that helps students improve their writing skills. Elm’s stability ensures that NoRedInk’s complex interface remains predictable and maintainable.
2. Rakuten
The global e-commerce giant Rakuten has used Elm in its frontend applications, benefiting from type safety and easy refactoring.
3. Norway’s Railway System
A surprising but powerful application—parts of Norway’s railway infrastructure use Elm for mission-critical systems, proving its reliability in high-stakes environments.
4. Blissfully
A SaaS company that utilizes Elm’s predictable and structured development environment to scale its platform efficiently.
5. GWI
A global market research company integrating Elm for frontend stability and maintainability in a competitive industry.
Why Elm’s Minimalism Works for Large Projects
Even though Elm rarely changes, it remains highly effective for building large-scale applications. Why?
1. Stability Over Time
Projects written in Elm years ago still work without modification. Unlike JavaScript frameworks that demand constant upgrades, Elm applications remain stable and easy to maintain.
2. Predictable Performance
Elm’s strong type system and immutability prevent runtime exceptions, ensuring applications run smoothly and consistently.
3. No Bloat, Just Essentials
Elm’s small core libraries contain only the necessary functions, preventing feature creep. Developers can focus on building applications instead of navigating unnecessary complexities.
4. Joyful Development Experience
Elm’s compiler messages are legendary—clear, informative, and helpful, making debugging a delight instead of a frustration. Developers spend less time fixing errors and more time writing quality code.
Conclusion
Elm stands as a testament to the power of removing features rather than adding them. By focusing on simplicity, stability, and practicality, Elm has remained one of the most enjoyable and reliable programming languages for web development. While other languages chase trends and introduce bloat, Elm thrives by doing less, but doing it well.
If you’re tired of languages that constantly change and introduce unnecessary complexity, Elm might be the perfect choice for your next project.
What do you think of Elm’s minimalist approach? Have you experienced the benefits of its simplicity firsthand? Let’s discuss in the comments!
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