https://github.com/sparksp/elm-review-always

elm-review rule to forbid always
https://github.com/sparksp/elm-review-always

always elm elm-review

Last synced: 8 days ago
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elm-review rule to forbid always

• Host: GitHub
• URL: https://github.com/sparksp/elm-review-always
• Owner: sparksp
• License: mit
• Created: 2020-05-12T09:27:29.000Z (over 4 years ago)
• Default Branch: master
• Last Pushed: 2024-08-11T06:37:59.000Z (3 months ago)
• Last Synced: 2024-08-11T07:39:08.159Z (3 months ago)
• Topics: always, elm, elm-review
• Language: Elm
• Homepage: https://package.elm-lang.org/packages/sparksp/elm-review-always/latest/
• Size: 865 KB
• Stars: 2
• Watchers: 3
• Forks: 0
• Open Issues: 3
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

        
# elm-review-always

![elm package](https://img.shields.io/elm-package/v/sparksp/elm-review-always)

![elm-review 2.0](https://img.shields.io/badge/elm--review-2.0-%231293D8)

![elm 0.19](https://img.shields.io/badge/elm-0.19-%231293D8)

![Tests](https://github.com/sparksp/elm-review-always/workflows/Tests/badge.svg)

Provides an [`elm-review`](https://package.elm-lang.org/packages/jfmengels/elm-review/latest/) rule to forbid the use of `always`.

## Use an [anonymous function] `\_ ->` instead of [`always`][always].

It's more concise, more recognizable as a function, and makes it easier to change your mind later and name the argument.

```elm

-- Don't do this --

List.map (always 0) [ 1, 2, 3, 4 ]

-- Instead do this --

List.map (\_ -> 0) [ 1, 2, 3, 4 ]

```

[always]: https://package.elm-lang.org/packages/elm/core/latest/Basics#always

[anonymous function]: https://elm-lang.org/docs/syntax#functions

## Example configuration

```elm

import NoAlways

import Review.Rule exposing (Rule)

config : List Rule

config =

    [ NoAlways.rule

    ]

```

## Caution: Heavy Computation

If the value you always want is the result of some heavy computation then you will not want that within an anonymous function as the work will be done every time. Instead, do the calculation in a nearby [`let..in`][let-expression] block first.

```elm

-- Don't do this --

List.map (always (heavyComputation arg1 arg2)) [ 1, 2, 3, 4 ]

-- Don't do this either --

List.map (\_ -> heavyComputation arg1 arg2) [ 1, 2, 3, 4 ]

-- Instead do this --

let

    heavyComputationResult =

        heavyComputation arg1 arg2

in

List.map (\_ -> heavyComputationResult) [ 1, 2, 3, 4 ]

-- This works too (but is less readable) --

List.map ((\value _ -> value) (heavyComputation arg1 arg2)) [ 1, 2, 3, 4 ]

```

[let-expression]: https://elm-lang.org/docs/syntax#let-expressions

## Try it out

You can try the example configuration above out by running the following command:

```bash

elm-review --template sparksp/elm-review-always/example

```