Review.Pattern.As

Forbid ... as ..variable.. patterns.

config =
    [ Review.Pattern.As.forbid
    ]

For example

view ({ windowSize } as model) =
    Html.text "Hello!"

will be fixed to

view model =
    let
        { windowSize } =
            model
    in
    Html.text "Hello!"

This fix doesn't try to merge this destructuring into existing lets. Add jfmengels/elm-review-simplify will do this for you.

why

as can quickly lead to barely readable, long patterns:

Node _ (Expression.Lambda ({ argumentPatterns, resultExpression, arrowRange } as lambda)) ->
    x

compared to

Node _ (Expression.Lambda lambda) ->
    let
        { argumentPatterns, resultExpression, arrowRange } =
            lambda
    in
    x

less syntax to learn to use right and keep in your head

as in case of patterns can create variables with types that know less than you:

highestScoreUi ... =
    case computeScores ... of
        [] ->
            textUi "no scores, yet"


        (head :: _) as scores ->
            case List.maximum scores of
                -- This can never happen
                Nothing ->
                    -- so we'll just use the head
                    scoreUi head


                Just highestFound ->
                    scoreUi highestFound

compared to

highestScoreUi ... =
    case computeScores ... of
        [] ->
            textUi "no scores, yet"


        scoresHead :: scoresTail ->
            scoreUi (List.Nonempty.maximum ( scoresHead, scoresTail ))

There are many more reasons for not introducing variables like that, see VariablesBetweenCaseOf.AccessInCases.forbid.

lue-bird/elm-review-pattern/1.0.0

Review.Pattern.As

why

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