https://github.com/lue-bird/elm-review-multiple-append-to-concat

elm-review: replace multiple `++` in sequence with concat
https://github.com/lue-bird/elm-review-multiple-append-to-concat

append concat elm elm-review plus-plus

Last synced: about 1 month ago
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elm-review: replace multiple `++` in sequence with concat

• Host: GitHub
• URL: https://github.com/lue-bird/elm-review-multiple-append-to-concat
• Owner: lue-bird
• License: mit
• Created: 2023-08-11T10:02:39.000Z (over 1 year ago)
• Default Branch: main
• Last Pushed: 2024-03-02T21:22:16.000Z (10 months ago)
• Last Synced: 2024-10-19T05:31:54.122Z (2 months ago)
• Topics: append, concat, elm, elm-review, plus-plus
• Language: Elm
• Homepage: https://dark.elm.dmy.fr/packages/lue-bird/elm-review-multiple-append-to-concat/latest/
• Size: 96.7 KB
• Stars: 1
• Watchers: 1
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • Changelog: changes.md
  • License: LICENSE

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README

        
# elm-review-multiple-append-to-concat

Provides the [`elm-review`](https://package.elm-lang.org/packages/jfmengels/elm-review/latest/) rule

[🔧`MultipleAppendToConcat`](https://package.elm-lang.org/packages/lue-bird/elm-review-multiple-append-to-concat/1.0.2/MultipleAppendToConcat/)

that replaces multiple `++` in sequence with concat, like

```elm

combinedString =

    "Your name is "

        ++ (nameParts

                |> String.join " "

           )

        ++ " and your age is "

        ++ (age |> String.fromInt)

        ++ "."

```

fixed to

```elm

combinedString =

    String.concat

        [ "Your name is "

        , nameParts

            |> String.join " "

        , " and your age is "

        , age |> String.fromInt

        , "."

        ]

```

and for lists

```elm

combinedList =

    a

        ++ [ b, c ]

        ++ d

```

fixed to

```elm

combinedList =

    List.concat

        [ a

        , [ b, c ]

        , d

        ]

```

  - `elm-review` doesn't have type inference, so for values like `a ++ b ++ c` this rule doesn't provide a fix

  - It is highly, highly recommended to use [`elm-review-simplify`](https://dark.elm.dmy.fr/packages/jfmengels/elm-review-simplify/latest/) alongside which simplifies

      - `[ a, b ] ++ [ c, d ]` to `[ a, b, c, d ]`

      - `[] ++ [ b, c ]` to `[ b, c ]`

      - `[ a ] ++ b ++ c` to `a :: b ++ c` etc

## why

#### it's more readable

This is somewhat subjective. Make sure everyone thinks the same before enabling the rule.

```elm

someDeclaration =

    let

        combinedList =

            (a

                ++ ([ b, c ]

                        |> List.map .name

                   )

                ++ d

            )

                |> String.join ", "

    in

    ...

```

vs

```elm

someDeclaration =

    let

        combinedList =

            [ a

            , [ b, c ]

                |> List.map .name

            , d

            ]

                |> List.concat

                |> String.join ", "

    in

    ...

```

#### less `appendable` and infix operators

`String.concat` and `List.concat` take concrete types and don't have the "magic-ness" of constrained type variables, operator precedence etc.

## try it out

```bash

elm-review --template lue-bird/elm-review-multiple-append-to-concat/example

```

If you like what it does, install it to your `review/` project and

## configure it

```elm

module ReviewConfig exposing (config)

import MultipleAppendToConcat

import Review.Rule exposing (Rule)

config : List Rule

config =

    [ MultipleAppendToConcat.rule MultipleAppendToConcat.ApplyList

    ]

```