Give Elm a Chance (newCodeCamp)

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  Give Elm a Chance! Joel Clermont  @jclermont

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Hello audience

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Goal  You leave here wanting to  play with Elm for an afternoon

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What to expect Elm language tour

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What to expect What is Elm?

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What to expect Why bother with Elm instead of Javascript?

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What to expect What makes Elm useful and interesting? • Code that doesn’t crash • A powerful type system • Ecosystem: quality over quantity • Care-free refactoring • Amazing QA / debug experience

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What is Elm?

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What is Elm? Elm is a language that compiles to JS

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What is Elm? Elm (currently) targets the browser

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What is Elm? Elm does not replace PHP, C#, Elixir, etc

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What is Elm? Elm does not (yet) replace JavaScript

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The Elm Architecture

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Language + Framework

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Model

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Update

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View

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No side effects

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Questions?

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Why bother with Elm instead of Javascript?

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Why bother with Elm instead of Javascript? User interfaces get complex quickly

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Questions?

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No runtime exceptions

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No runtime exceptions • Hooray, no bugs! Not quite.

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No runtime exceptions • Hooray, no bugs! Not quite. • Runtime exceptions are a common class of bugs

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No runtime exceptions • Hooray, no bugs! Not quite. • Runtime exceptions are a common class of bugs • “undeﬁned is not a function”

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No Red Ink’s testimonial Since we began using Elm in 2015, our production Elm code has yet to cause a single runtime exception. Our error logs show plenty of crashes from our legacy JavaScript code, but none from our Elm code. We've also found our Elm-powered front-end substantially easier to scale than our previous React code base.

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Spot the error

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Pattern matching

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Error handling in types

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Questions?

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The power of the type system

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The power of the type system • PHP’s type system is getting better, but still basic

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The power of the type system • PHP’s type system is getting better, but still basic • C# and Java? Better yet, but not very expressive

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The power of the type system • PHP’s type system is getting better, but still basic • C# and Java? Better yet, but not very expressive • ML type system

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Algebraic data types

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Data modeling!! https://youtu.be/IcgmSRJHu_8

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Questions?

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Ecosystem

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Elm ecosystem • Package manager enforces semantic versioning

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Elm ecosystem • Package manager enforces semantic versioning • API design is extremely thoughtful

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Elm ecosystem • Package manager enforces semantic versioning • API design is extremely thoughtful • Awesome tooling!

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Compiler

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Editors

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Editors

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Editors

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Editors

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Editors

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Debugger http://elm-lang.org/assets/blog/0.18/todomvc.html

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Ellie https://ellie-app.com/kLKCgY6sK9/0

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Questions?

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My story with Elm

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My ﬁnal sales pitch • Welcoming community • Lots of effort to making concepts accessible • Easy to use it gradually • Will make you a better JavaScript developer

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Closing survey

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Next steps • http://elm-lang.org (live demos, debugger, REPL) • https://guide.elm-lang.org/ • https://www.elm-tutorial.org • https://pragmaticstudio.com/elm • https://frontendmasters.com/courses/elm/ • https://uwm.edu/business/research/centers-institutes/technology- innovation/cti-workshop-series/ • https://www.dailydrip.com/topics/elm • @elmlang @czaplic @rtfeldman @jclermont