gren-lang/core

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Gren's core package

Stars: 48
Forks: 14
Open beginner issues: 0
Indexed issues: 62
Avg merge: 4h 14m
Merged PRs (30d): 1

Dominant language: JavaScript
License: No license data
Last GitHub push: Sep 10, 2026
Latest indexed: Sep 20, 2026
Contributing guide: Contributing guide
Code of conduct: No code of conduct
Beginner labels: help wanted good first issue

Beginner friendly Everything

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62 open issues indexed

`Bytes.toString` drops a leading U+FEFF, so a string does not survive `fromString` and back Open

bug

Difficulty 2/5 1-3 hours Newbie friendliness 75/100

gren-lang/core#155 · Opened Sep 14, 2026
`Bytes.Decode.bytes` reads past the end of the `Bytes` it is decoding Open

bug

Difficulty 2/5 1-3 hours Newbie friendliness 78/100

gren-lang/core#154 · Opened Sep 14, 2026
A `Bytes` value crossing a port carries its whole backing buffer, not the bytes it holds Open

bug

Difficulty 2/5 1-3 hours Newbie friendliness 78/100

gren-lang/core#153 · Opened Sep 14, 2026
A decoder that uses `Bytes.Decode.fail` crashes instead of returning `Nothing` Open

bug

Difficulty 3/5 1-2 days Newbie friendliness 55/100

gren-lang/core#152 · Opened Sep 14, 2026
`String.words` of a string with no words in it returns a 1-member Array instead of an empty Array Open

bug

Difficulty 2/5 1-3 hours Newbie friendliness 72/100

gren-lang/core#151 · Opened Sep 13, 2026
`firstIndexOf` can return an index that `slice` cannot use: what it found is half a character Open

bug

Difficulty 4/5 3-5 days Newbie friendliness 55/100

gren-lang/core#150 · Opened Sep 12, 2026
`Char.fromCode` throws a `RangeError` out of range, but its documentation says it returns U+FFFD Open

bug

Difficulty 2/5 1-3 hours Newbie friendliness 78/100

gren-lang/core#149 · Opened Sep 12, 2026
firstIndexOf, lastIndexOf and indices return UTF-16 offsets, which no other String function accepts Open

bug

Difficulty 3/5 1-2 days Newbie friendliness 72/100

gren-lang/core#148 · Opened Sep 12, 2026
`Random.int` uses its range modulo 2^32: wide ranges silently narrow, and 2^32 + 1 returns the low end of its range forever Open

bug

Difficulty 4/5 3-5 days Newbie friendliness 48/100

gren-lang/core#147 · Opened Sep 11, 2026
`Random` 's PCG algorithm is incorrect: `peel`'s multiply overflows float64 Open

bug

Difficulty 2/5 1-3 hours Newbie friendliness 82/100

gren-lang/core#146 · Opened Sep 11, 2026
`String.Parser.keyword` treats every non-ASCII letter as a word boundary; compiler-common's parser thus disagrees with the Haskell-based parser Open

bug

Difficulty 4/5 3-5 days Newbie friendliness 52/100

gren-lang/core#144 · Opened Sep 7, 2026
`compare` on `String` orders UTF-16 code units, not characters Open

Difficulty 3/5 1-2 days Newbie friendliness 68/100

gren-lang/core#143 · 2 comments · Opened Sep 6, 2026
An exception raised after a stream write is swallowed, and the scheduler stops for good Open

bug

Difficulty 4/5 3-5 days Newbie friendliness 48/100

gren-lang/core#142 · Opened Sep 5, 2026
`remainderBy 0` puts `NaN` in an `Int`, while its sibling `modBy 0` kills the program Open

bug

Difficulty 3/5 1-2 days Newbie friendliness 68/100

gren-lang/core#141 · 1 comment · Opened Sep 5, 2026
`^` with a negative exponent puts `0.5` and `Infinity` into an `Int` Open

bug

Difficulty 3/5 1-2 days Newbie friendliness 58/100

gren-lang/core#140 · Opened Sep 5, 2026
`compare` on floats is not an order, and a NaN key makes `Dict` lose entries it still lists Open

bug

Difficulty 4/5 3-5 days Newbie friendliness 52/100

gren-lang/core#139 · Opened Sep 5, 2026
`chompIf` / `chompWhile` hand the predicate half a surrogate pair Open

bug

Difficulty 2/5 1-3 hours Newbie friendliness 88/100

gren-lang/core#138 · Opened Sep 3, 2026
Bytes.flatten reads each input from offset 0 of its backing buffer even when it shouldn't Open

bug

Difficulty 2/5 1-3 hours Newbie friendliness 72/100

gren-lang/core#137 · 1 comment · Opened Aug 16, 2026
_Scheduler_step re-enters parked bindings, corrupting effect manager state ; crash happens Open

bug

Difficulty 4/5 3-5 days Newbie friendliness 48/100

gren-lang/core#136 · Opened Aug 16, 2026
Time.here is missing eras Open

Difficulty 4/5 3-5 days Newbie friendliness 55/100

gren-lang/core#124 · 17 comments · Opened Feb 9, 2026
JSON: Replace `value.hasOwnProperty` with `Object.prototype.hasOwnProperty.call` Open

enhancement

Difficulty 1/5 Under an hour Newbie friendliness 55/100

gren-lang/core#116 · Opened Aug 18, 2025
Improve JSON encode performance Open

enhancement

Difficulty 5/5 Over a week Newbie friendliness 20/100

gren-lang/core#115 · 1 comment · Opened Aug 7, 2025
Is it possible to add `Stream.waitForLock`? Open

Difficulty 5/5 Over a week Newbie friendliness 35/100

gren-lang/core#114 · 1 comment · Opened Jul 25, 2025
Add `Sub.keepIf` and `Sub.mapAndKeepJust` Open

Difficulty 3/5 1-2 days Newbie friendliness 35/100

gren-lang/core#112 · Opened Jul 24, 2025
Change runtime representation of `Bytes` to `UInt8Array` Open

Difficulty 4/5 3-5 days Newbie friendliness 45/100

gren-lang/core#111 · 1 reaction · Opened Jul 24, 2025
cross-platform HttpClient Open

Difficulty 4/5 3-5 days Newbie friendliness 35/100

gren-lang/core#110 · 2 comments · 1 reaction · Opened Jul 18, 2025
Cross-platform HTML module Open

Difficulty 5/5 Over a week Newbie friendliness 25/100

gren-lang/core#109 · Opened Jul 18, 2025
bytes to hex Open

enhancement good first issue help wanted

Difficulty 3/5 1-2 days Newbie friendliness 35/100

gren-lang/core#98 · 1 reaction · Opened Mar 4, 2025
Add Task.onComplete Open

Difficulty 3/5 1-2 days Newbie friendliness 45/100

gren-lang/core#86 · 2 reactions · Opened Jun 26, 2024
modBy crashes if given a zero Open

Difficulty 4/5 3-5 days Newbie friendliness 35/100

gren-lang/core#85 · 5 comments · 1 reaction · Opened Apr 29, 2024
Provide a way to unmount, or cleanup, a Gren application once it's started Open

enhancement

Difficulty 5/5 Over a week Newbie friendliness 32/100

gren-lang/core#36 · Opened Sep 17, 2022
`Result.Err` recovering Open

enhancement

Difficulty 5/5 Over a week Newbie friendliness 35/100

gren-lang/core#34 · Opened Aug 9, 2022
decoding implementation produces runtime exception → `Nothing` Open

Difficulty 3/5 1-2 days Newbie friendliness 30/100

gren-lang/core#47 · Opened Aug 9, 2022
`Bytes.encoder/decoder` add Open

Difficulty 5/5 Over a week Newbie friendliness 20/100

gren-lang/core#49 · Opened Aug 9, 2022
"weird math because of js" Open

bug

Difficulty 5/5 Over a week Newbie friendliness 20/100

gren-lang/core#33 · Opened Aug 8, 2022
`==` on `Value`s of different shape misbehaves Open

Difficulty 4/5 3-5 days Newbie friendliness 25/100

gren-lang/core#42 · Opened Aug 8, 2022
`port`s inside `Cmd.batch` are called asynchronously Open

bug

Difficulty 4/5 3-5 days Newbie friendliness 25/100

gren-lang/core#31 · Opened Aug 8, 2022
setting `Date.prototype._nth = null;` from js → Uncaught TypeError Open

bug help wanted

Difficulty 4/5 3-5 days Newbie friendliness 20/100

gren-lang/core#29 · Opened Aug 8, 2022
`Dict.get` with `List` keys on `--optimize`: unreliable Open

Difficulty 4/5 3-5 days Newbie friendliness 15/100

gren-lang/core#28 · 1 comment · Opened Aug 8, 2022
`port` sending an unexpected value → uninformative error message Open

enhancement help wanted

Difficulty 3/5 1-2 days Newbie friendliness 25/100

gren-lang/core#26 · Opened Aug 8, 2022
runtime exception in `subscribe` → side effects stop working Open

bug good first issue help wanted

Difficulty 4/5 3-5 days Newbie friendliness 20/100

gren-lang/core#25 · Opened Aug 8, 2022
`List.repeat Infinity` → out of memory exception Open

bug

Difficulty 4/5 3-5 days Newbie friendliness 25/100

gren-lang/core#13 · 1 comment · Opened Aug 8, 2022
`port` declarations order in resulting js influences behavior Open

bug help wanted

Difficulty 4/5 3-5 days Newbie friendliness 25/100

gren-lang/core#12 · Opened Aug 8, 2022
`_Platform_gatherEffects` can throw runtime exception - Maximum call stack size exceeded Open

bug help wanted

Difficulty 4/5 3-5 days Newbie friendliness 25/100

gren-lang/core#9 · Opened Aug 8, 2022
subscription not receiving response Open

bug help wanted

Difficulty 3/5 1-2 days Newbie friendliness 15/100

gren-lang/core#8 · Opened Aug 8, 2022
`Regex.find` with loose regex matches only the first Open

Difficulty 3/5 1-2 days Newbie friendliness 15/100

gren-lang/core#52 · Opened Aug 8, 2022
regression: capture groups can't match `""` Open

Difficulty 3/5 1-2 days Newbie friendliness 20/100

gren-lang/core#53 · Opened Aug 8, 2022
`split` doesn't include capture groups in results Open

Difficulty 3/5 1-2 days Newbie friendliness 20/100

gren-lang/core#55 · Opened Aug 8, 2022
documentation: point out browser irregularities Open

Difficulty 2/5 1-3 hours Newbie friendliness 25/100

gren-lang/core#56 · Opened Aug 8, 2022
Zone transitions don't take effect on their start times Open

Difficulty 4/5 3-5 days Newbie friendliness 15/100

gren-lang/core#77 · Opened Aug 8, 2022

gren-lang/core

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