Elm 0.19 TL;DR • CANENA

As the Elm 0.19 upgrade docs are lacking some vital information you only know about by consistently hanging out on the Elm Slack I thought I’d list them here for all the word to see.

Massive compile time improvements
Huge internal rework of the compiler that is prepared for the coming use-cases
Many bugfixes regarding performance - i.e. pattern matching on tuples, many case branches, unnecessary recompiles, too much IO, memory leaks
Removed many XSS attack vectors - i.e. disallowing innerHTML and inline event handlers
Removed user defined operators, i.e. no more Narsil operators in user code :slightly_smiling_face: <==|[======>
The already unpublished Native was renamed to Kernel and is no longer usable in user code, it always has been an implementation detail of the platform, native code is also built differently than before. Only elm and elm-explorations Github organizations can have effect Modules and Kernel code
Many modules have been moved out of the Elm core to be able to update them separately without having to release a new language version
Dead Code Elimination in production builds - smaller builds, opportunity for clever usage of compiler knowledge to improve runtime with --optimize flag for elm make
New elm.json format that includes test dependencies and supports the distinction of libraries and applications
Array is now faster and has some significant bugfixes
The magic polymorphic toString has been removed in favor of specialized functions like String.fromInt and the like
No more Debug.crash in production but is renamed to Debug.todo in debug mode
Event, port and message handling is now synchronous by default (you can opt-in to async on demand) which supports cases where events in the DOM have to be handled synchronously, i.e. the Clipboard API
Initialization on the JS side is done uniformly via Elm.Main.init({ flags: {}, node: document.querySelector("#root") })
There is now elm/browser which contains navigation, page eventhandling and page visibility APIs
Browser.application with full SPA routing
Browser.document set <title>, control <body>
Browser.element simple TEA “widget”
Browser.sandbox simplified beginner program
In addition to ports WebComponents are proposed for specific use cases of JS interop
The compiler can now be built with Haskell Stack - lts-11.20 for GHC 8.2.2 for now

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