# Learn

**URL:** https://discourse.elm-lang.org/c/learn/6.md?page=5

[Latest](https://discourse.elm-lang.org/latest.md) · [Categories](https://discourse.elm-lang.org/categories.md)

**Page:** 6

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## [What is "toHtml" that WebGL Elm is using?](https://discourse.elm-lang.org/t/what-is-tohtml-that-webgl-elm-is-using/9499)

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**Author:** [@demensdeum](https://discourse.elm-lang.org/u/demensdeum)\
**Replies:** 8\
**Last updated:** [December 5, 2023, 7:46pm UTC](https://discourse.elm-lang.org/t/what-is-tohtml-that-webgl-elm-is-using/9499 "2023-12-05T19:46:25Z")

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I am trying to write ThreeJS wrapper for Elm, and I am looking into WebGL Elm implementation. As I understand it does’nt use Elm ports, but just using direct JS calls/hacks? Can you help me to understand please? WebGL…

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## [Webapp local data synchronization service](https://discourse.elm-lang.org/t/webapp-local-data-synchronization-service/9405)

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**Author:** [@setop](https://discourse.elm-lang.org/u/setop)\
**Replies:** 13\
**Last updated:** [November 30, 2023, 5:12pm UTC](https://discourse.elm-lang.org/t/webapp-local-data-synchronization-service/9405 "2023-11-30T17:12:23Z")

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I have an elm application that has two ports to read and write key-value data currently persisted in the user web browser’s local storage. Now I’m looking for a service that would allow to sync data with an other device…

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## [Elm HTTP stream/chunk handling -- Elm n00b](https://discourse.elm-lang.org/t/elm-http-stream-chunk-handling-elm-n00b/9487)

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**Author:** [@James\_Smyth](https://discourse.elm-lang.org/u/James_Smyth)\
**Replies:** 1\
**Last updated:** [November 30, 2023, 8:04am UTC](https://discourse.elm-lang.org/t/elm-http-stream-chunk-handling-elm-n00b/9487 "2023-11-30T08:04:28Z")

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I’ve done a fair amount of research (ie. googling) and I’m not finding simple examples of how to use the Elm HTTP package, with what I think is the common paradigm, to process an http stream delivered in chunks(\*\*\*). I’…

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## [Whats the best way to test routing locally?](https://discourse.elm-lang.org/t/whats-the-best-way-to-test-routing-locally/9463)

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**Author:** [@cma256](https://discourse.elm-lang.org/u/cma256)\
**Replies:** 5\
**Last updated:** [November 17, 2023, 2:01pm UTC](https://discourse.elm-lang.org/t/whats-the-best-way-to-test-routing-locally/9463 "2023-11-17T14:01:07Z")

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I’m using Browser.application and elm reactor currently. When loading the app it visits “/src/Main.elm” rather than the root url (obviously). Clicking URLs within the application works fine but typing urls into the add…

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## [Avoid Nested Pattern Matching](https://discourse.elm-lang.org/t/avoid-nested-pattern-matching/9448)

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**Author:** [@JesterXL](https://discourse.elm-lang.org/u/JesterXL)\
**Replies:** 1\
**Last updated:** [November 11, 2023, 6:33am UTC](https://discourse.elm-lang.org/t/avoid-nested-pattern-matching/9448 "2023-11-11T06:33:50Z")

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What’s the recommendations to fix nested pattern matching that has more than 2 variations (e.g. something like RemoteData, not Result or Maybe)? Been stuck in TypeScript, and using their Unions, you have to use switch s…

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## [Changes/Releasenotes elm 0.19.1-6](https://discourse.elm-lang.org/t/changes-releasenotes-elm-0-19-1-6/9447)

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**Author:** [@Carsten\_Konig](https://discourse.elm-lang.org/u/Carsten_Konig)\
**Replies:** 4\
**Last updated:** [November 10, 2023, 2:05pm UTC](https://discourse.elm-lang.org/t/changes-releasenotes-elm-0-19-1-6/9447 "2023-11-10T14:05:27Z")

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Hi, I noticed a new npm package version was released 6 days ago. Does anyone know what has changed/was fixed? Or is this addressing dependencies only?

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## [How to Style my Elm application? (Beginner)](https://discourse.elm-lang.org/t/how-to-style-my-elm-application-beginner/9437)

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**Author:** [@Nikita0x](https://discourse.elm-lang.org/u/Nikita0x)\
**Replies:** 7\
**Last updated:** [November 7, 2023, 9:22pm UTC](https://discourse.elm-lang.org/t/how-to-style-my-elm-application-beginner/9437 "2023-11-07T21:22:24Z")

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Hi everbody. I have discovered Elm just recently and wanted to pick it up as my first functional programming language ( I am a junior front end react developer). How do I do CSS styling of my simple Elm application?

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## [Toggle password visibility](https://discourse.elm-lang.org/t/toggle-password-visibility/9441)

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**Author:** [@Daniel\_Malmgren\_de\_O](https://discourse.elm-lang.org/u/Daniel_Malmgren_de_O)\
**Replies:** 4\
**Last updated:** [November 6, 2023, 8:38pm UTC](https://discourse.elm-lang.org/t/toggle-password-visibility/9441 "2023-11-06T20:38:59Z")

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Hi, I am new to Elm and am trying to add a button that toggles the visibility of the password fields (either as the standard password type or as text) but while I can do that hard-coding the boolean, I am getting an err…

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## [Is there a way to test a binary file parser?](https://discourse.elm-lang.org/t/is-there-a-way-to-test-a-binary-file-parser/9412)

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**Author:** [@Atlewee](https://discourse.elm-lang.org/u/Atlewee)\
**Replies:** 4\
**Last updated:** [November 5, 2023, 12:56am UTC](https://discourse.elm-lang.org/t/is-there-a-way-to-test-a-binary-file-parser/9412 "2023-11-05T00:56:55Z")

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I’m creating a PDF parser in Elm and those files contains a lot of binary information. The parser expects Bytes as input as I want it optimized for File.load / Http.get ++ Testing is currently done by converting files …

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## [Elm Compiler Too Smart? Appears to delete function calls](https://discourse.elm-lang.org/t/elm-compiler-too-smart-appears-to-delete-function-calls/9424)

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**Author:** [@elmish](https://discourse.elm-lang.org/u/elmish)\
**Replies:** 9\
**Last updated:** [November 3, 2023, 5:01pm UTC](https://discourse.elm-lang.org/t/elm-compiler-too-smart-appears-to-delete-function-calls/9424 "2023-11-03T17:01:56Z")

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What may be going is that the Elm compiler recognizes we don’t use a return value, so it completely eliminates even calling this function. Here’s an example: port module Audio exposing (..) import Browser import Html …

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## ["The Economics of Programming Languages" by Evan Czaplicki (Strange Loop 2023)](https://discourse.elm-lang.org/t/the-economics-of-programming-languages-by-evan-czaplicki-strange-loop-2023/9376)

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**Author:** [@jhbrown](https://discourse.elm-lang.org/u/jhbrown)\
**Replies:** 26\
**Last updated:** [October 23, 2023, 8:54am UTC](https://discourse.elm-lang.org/t/the-economics-of-programming-languages-by-evan-czaplicki-strange-loop-2023/9376 "2023-10-23T08:54:20Z")

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Evan’s recent talk is now on video! Elm comes in toward the end, but definitely worth watching the whole talk! Jeremy

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## [Discourse enhancements](https://discourse.elm-lang.org/t/discourse-enhancements/9366)

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**Author:** [@kanishka](https://discourse.elm-lang.org/u/kanishka)\
**Replies:** 14\
**Last updated:** [October 17, 2023, 8:18am UTC](https://discourse.elm-lang.org/t/discourse-enhancements/9366 "2023-10-17T08:18:41Z")

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More moderators and tagging / sections for this elm-lang discourse. What is the reason for more moderators? It feels like no one is moderating the forum right now (or enabling new features available in recent dis…

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## [Current commonly used tool for previewing docs?](https://discourse.elm-lang.org/t/current-commonly-used-tool-for-previewing-docs/9388)

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**Author:** [@ShinyStack](https://discourse.elm-lang.org/u/ShinyStack)\
**Replies:** 4\
**Last updated:** [October 16, 2023, 4:16pm UTC](https://discourse.elm-lang.org/t/current-commonly-used-tool-for-previewing-docs/9388 "2023-10-16T16:16:12Z")

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Hi, What does this community tend to use these days for previewing docs of a module you’re working on? I see some posts about ‘elm-doc-preview’ from years ago. Is there a community consensus around good tools these day…

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## [Subscribes to multiple events](https://discourse.elm-lang.org/t/subscribes-to-multiple-events/9372)

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**Author:** [@setop](https://discourse.elm-lang.org/u/setop)\
**Replies:** 2\
**Last updated:** [October 14, 2023, 11:37am UTC](https://discourse.elm-lang.org/t/subscribes-to-multiple-events/9372 "2023-10-14T11:37:20Z")

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Hi all, I already managed to use port to plug on websocket or perform API call. But only one at a time. For a new project I need to have more than one port and I couldn’t get out of it. Here is some pseudo code of wha…

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## [Alternative to multidimensional array?](https://discourse.elm-lang.org/t/alternative-to-multidimensional-array/9365)

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**Author:** [@JesterXL](https://discourse.elm-lang.org/u/JesterXL)\
**Replies:** 6\
**Last updated:** [October 7, 2023, 1:43pm UTC](https://discourse.elm-lang.org/t/alternative-to-multidimensional-array/9365 "2023-10-07T13:43:17Z")

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Building a 2D game, and I’ve used multidimensional array’s in the past. However, the Array version in Elm is a bit unwieldy because of all the Maybe’s + nested rows. The grid is known ahead of time, and there won’t be re…

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## [React-query clone doesn't exist - not applicable or not enough demand?](https://discourse.elm-lang.org/t/react-query-clone-doesnt-exist-not-applicable-or-not-enough-demand/9371)

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**Author:** [@kanishka](https://discourse.elm-lang.org/u/kanishka)\
**Replies:** 2\
**Last updated:** [October 5, 2023, 12:07pm UTC](https://discourse.elm-lang.org/t/react-query-clone-doesnt-exist-not-applicable-or-not-enough-demand/9371 "2023-10-05T12:07:57Z")

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React query claims that it addresses: Caching... (possibly the hardest thing to do in programming) Deduping multiple requests for the same data into a single request Updating "out of date" data in the background Knowing…

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## [Is a update for the npm package a possibility?](https://discourse.elm-lang.org/t/is-a-update-for-the-npm-package-a-possibility/9358)

<div class="topic-metadata">

**Author:** [@Carsten\_Konig](https://discourse.elm-lang.org/u/Carsten_Konig)\
**Replies:** 4\
**Last updated:** [October 2, 2023, 6:28am UTC](https://discourse.elm-lang.org/t/is-a-update-for-the-npm-package-a-possibility/9358 "2023-10-02T06:28:43Z")

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Hi, first let me say sorry if this issue was answered lately - while I’m a regular Elm user I’m not really following the community here or elsewhere on a regular basis. In the last couple of months the npm packages has…

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## [Why does the parser fail to output the error message?](https://discourse.elm-lang.org/t/why-does-the-parser-fail-to-output-the-error-message/9361)

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**Author:** [@polarit](https://discourse.elm-lang.org/u/polarit)\
**Replies:** 4\
**Last updated:** [September 30, 2023, 7:26am UTC](https://discourse.elm-lang.org/t/why-does-the-parser-fail-to-output-the-error-message/9361 "2023-09-30T07:26:47Z")

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This is probably a trivial issue for an experienced code writer but very frustrating to me as trying to solve it couple of days already. . The basic simple example It works as expected and outputs error messages if …

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## [Nonsensical error in elm-language-server](https://discourse.elm-lang.org/t/nonsensical-error-in-elm-language-server/9354)

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**Author:** [@peacememories](https://discourse.elm-lang.org/u/peacememories)\
**Replies:** 7\
**Last updated:** [September 27, 2023, 11:37am UTC](https://discourse.elm-lang.org/t/nonsensical-error-in-elm-language-server/9354 "2023-09-27T11:37:07Z")

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I’ve run into something I hadn’t experienced at all while using elm so far - a completely wrong error report. The code in question is this: -- ... import Json.Decode as JD import Json.Decode.Extra as JD import Json.De…

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## [Are the stdlib repos abandonware?](https://discourse.elm-lang.org/t/are-the-stdlib-repos-abandonware/9345)

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**Author:** [@mpldr](https://discourse.elm-lang.org/u/mpldr)\
**Replies:** 11\
**Last updated:** [September 23, 2023, 2:33pm UTC](https://discourse.elm-lang.org/t/are-the-stdlib-repos-abandonware/9345 "2023-09-23T14:33:40Z")

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Hi, I discovered Elm quite recently and was curious if the stdlib packages like Html are abandoned, seeing how there are already a number of exclusively positive additions (fixed typos, recently™ added elements, and so o…

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## [Json.Decode into Union Type without an identifier](https://discourse.elm-lang.org/t/json-decode-into-union-type-without-an-identifier/9335)

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**Author:** [@spruce\_moose](https://discourse.elm-lang.org/u/spruce_moose)\
**Replies:** 4\
**Last updated:** [September 18, 2023, 5:42pm UTC](https://discourse.elm-lang.org/t/json-decode-into-union-type-without-an-identifier/9335 "2023-09-18T17:42:01Z")

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Hi! Very new to learning Elm and was wondering if someone could help simplify a bit of JSON decoding logic or maybe explain the best practice to do what I’ve done. Basic problem is I have a JSON endpoint that gives me …

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## [Can elm-pages-v3 help with compile times for large CRUD applications?](https://discourse.elm-lang.org/t/can-elm-pages-v3-help-with-compile-times-for-large-crud-applications/9319)

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**Author:** [@kanishka](https://discourse.elm-lang.org/u/kanishka)\
**Replies:** 2\
**Last updated:** [September 14, 2023, 10:23am UTC](https://discourse.elm-lang.org/t/can-elm-pages-v3-help-with-compile-times-for-large-crud-applications/9319 "2023-09-14T10:23:21Z")

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Does elm-pages-v3 create one elm app per page? If so, can it help keep compile times (and compiler memory usage) constant as the number of pages grows?

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## [Elm parser tried first time - results not as expected](https://discourse.elm-lang.org/t/elm-parser-tried-first-time-results-not-as-expected/9313)

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**Author:** [@polarit](https://discourse.elm-lang.org/u/polarit)\
**Replies:** 5\
**Last updated:** [September 11, 2023, 8:01pm UTC](https://discourse.elm-lang.org/t/elm-parser-tried-first-time-results-not-as-expected/9313 "2023-09-11T20:01:14Z")

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I aimed to create a parser getting the point (x,y) from the input string " (1.25, 2.50) " The parsing result looks correct: Ok { x = 1.25, y = 2.5 } However, this is not the record { x = 1.25, y = 2.5 } of alias type …

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## [File Upload not very concise](https://discourse.elm-lang.org/t/file-upload-not-very-concise/9302)

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**Author:** [@WilhElm](https://discourse.elm-lang.org/u/WilhElm)\
**Replies:** 3\
**Last updated:** [September 4, 2023, 11:11am UTC](https://discourse.elm-lang.org/t/file-upload-not-very-concise/9302 "2023-09-04T11:11:09Z")

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Hey guys, I’m rather new to elm and it is my first language in the ML family. Right now I’m trying to do the AOC 2022 in order to get the hang of it and the first issue is the file selection. I got it to work but I ha…

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## [Isometric games like 8bit ones](https://discourse.elm-lang.org/t/isometric-games-like-8bit-ones/9306)

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**Author:** [@gargoris](https://discourse.elm-lang.org/u/gargoris)\
**Replies:** 1\
**Last updated:** [September 3, 2023, 10:01am UTC](https://discourse.elm-lang.org/t/isometric-games-like-8bit-ones/9306 "2023-09-03T10:01:09Z")

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This one could sound rather silly for the rest, but I’m a bit lost. I’m just jump recently back on my high school isometric games for Spectrum/msx and just feel some interest in trying to learn and code something simila…

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## [Quickstart learning envs (e.g. ellie) - current favorites?](https://discourse.elm-lang.org/t/quickstart-learning-envs-e-g-ellie-current-favorites/9294)

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**Author:** [@kanishka](https://discourse.elm-lang.org/u/kanishka)\
**Replies:** 4\
**Last updated:** [September 1, 2023, 5:29pm UTC](https://discourse.elm-lang.org/t/quickstart-learning-envs-e-g-ellie-current-favorites/9294 "2023-09-01T17:29:38Z")

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I’m curious about what people are using currently when they want a minimal fuss learning environment for people building up their elm core syntax and library skills that only needs a browser? ellie codespace/gitpod w/e…

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## [How to initiate an event from update](https://discourse.elm-lang.org/t/how-to-initiate-an-event-from-update/9300)

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**Author:** [@bwanab](https://discourse.elm-lang.org/u/bwanab)\
**Replies:** 2\
**Last updated:** [August 31, 2023, 2:00pm UTC](https://discourse.elm-lang.org/t/how-to-initiate-an-event-from-update/9300 "2023-08-31T14:00:41Z")

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I have a process that takes several seconds to complete, but I want to ensure that the user gets immediate feedback that what they’ve done was initiated. So, when they click on a active cell in a table for example, I wan…

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## [Polymorphic html tag with builder pattern](https://discourse.elm-lang.org/t/polymorphic-html-tag-with-builder-pattern/9298)

<div class="topic-metadata">

**Author:** [@Dino\_Pascale](https://discourse.elm-lang.org/u/Dino_Pascale)\
**Replies:** 6\
**Last updated:** [August 31, 2023, 8:10am UTC](https://discourse.elm-lang.org/t/polymorphic-html-tag-with-builder-pattern/9298 "2023-08-31T08:10:49Z")

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Hello everyone! First post here, but I lurked for a long time with another account :smile: I have a problem with a design system built in Elm. I’m implementing a component with the builder pattern that render into an h2 …

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## [Old question: elm-spa: Cant Refresh the page or manually enter url](https://discourse.elm-lang.org/t/old-question-elm-spa-cant-refresh-the-page-or-manually-enter-url/9288)

<div class="topic-metadata">

**Author:** [@LTstrange](https://discourse.elm-lang.org/u/LTstrange)\
**Replies:** 3\
**Last updated:** [August 27, 2023, 3:06am UTC](https://discourse.elm-lang.org/t/old-question-elm-spa-cant-refresh-the-page-or-manually-enter-url/9288 "2023-08-27T03:06:46Z")

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Hi, I’m pretty new to elm and front-end. And I encountered the same problem which has been solved in this previous post 4088, but it didnt work for me. edit: Neither worked on github.io, here is my github repository, i…

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## [Elm Bootstrap. Fixed aspect ratio broken in Safari](https://discourse.elm-lang.org/t/elm-bootstrap-fixed-aspect-ratio-broken-in-safari/9283)

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**Author:** [@bwanab](https://discourse.elm-lang.org/u/bwanab)\
**Replies:** 2\
**Last updated:** [August 25, 2023, 11:32am UTC](https://discourse.elm-lang.org/t/elm-bootstrap-fixed-aspect-ratio-broken-in-safari/9283 "2023-08-25T11:32:46Z")

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I’ve built a simple Othello/Reversi app as a front end to a machine learning project I’ve been doing to implement an Othello playing bot. I’m not a front end dev, but I know a lot more about it now than I did a week ago …

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