Highway
to
Elm
Highway
to
Elm
Front-end is dominated by
JavaScript is backward compatible
Biggest advantage
Biggest disadvantage
You can't deprecate things !!! 😱
null > 0 // false
null == 0 // false
null >= 0 // ... trueJS syntax size
Time
ES6
A LOT to learn!
- The language is complex
- Many ways to do the same thing
- Framework choice / learning
- Tooling
Hard to optimize
- Dead code elimination / Tree shaking
- Assets size
- Complex build
Low confidence level
- Minor IDE assistance
- Refactoring is painful
- Slow feedback cycle: runtime
- Dependencies are risky
By Chris Williams
Elm is a typed functional language to create fast and reliable web applications
Websites and webapps
Domain specific
Statically typed
- Many bugs don't compile
- IDE can help you
- Refactoring is compiler-driven
- Feedback cycle is really fast
No Runtime Exceptions
17K+ LoC
200K+ LoC
Declarative, not imperative
const myNumbers = [1, 2, 3, 4, 5];
let squaredNumbers = [];
for(number of myNumbers) {
squaredNumbers.push(number * number);
}const myNumbers = [1, 2, 3, 4, 5];
const squaredNumbers = myNumbers
.map(number => number * number);
Honesty
function sendEmail(user) {
}No unwanted side-effect
function sendEmail(user) {
if (user.email === null) {
throw new Error('No email provided for the user');
}
}function sendEmail(user) {
if (user.email === null) {
throw new Error('No email provided for the user');
}
launchNuclearMissile();
}Side-effect = command, explicitely declared
Fast
- Everything is pure => optimizations
- Small assets
"Elm has a very strong emphasis on simplicity, ease-of-use, and quality tooling."
Simplicity, ease of use
- Focused on one purpose
- Syntax removal
- Well-thought API
- Compiler helps you
- Explicitness
Quality tooling
- Compiler
- Project starter
- Package manager
- Dev environment
- REPL
- Tests runner
- Doc tool
Enforced documentation
Enforced versioning
1.2.3
Nothing changed for the outside
Something was added
Something has changed
Great community
See also Building Trust: What Has Worked by Richard Feldman
and What is success? by Evan Czaplicki
Syntax
-- a single line comment
{- a
multiline
comment
-}Comments
Advantages
- Great developer experience
- No runtime exceptions
- Great debugger
- Powerful type system
- Great performances
- Great community
Drawbacks
- Opinionated governance model
- Boilerplate vs Explicitness
- Not for every use case
Why use Elm?
- Complex UI / Model
- Frequent refactoring
- You care for bugs
- Easy introduction to FP
- Write better code
Introduction Hackathon Elm
By ereold
