https://github.com/panosoft/elm-node-main

Node main for Server-side Elm programs
https://github.com/panosoft/elm-node-main

Last synced: 2 months ago
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Node main for Server-side Elm programs

• Host: GitHub
• URL: https://github.com/panosoft/elm-node-main
• Owner: panosoft
• License: unlicense
• Created: 2016-09-12T21:14:36.000Z (over 8 years ago)
• Default Branch: master
• Last Pushed: 2017-03-28T14:40:04.000Z (almost 8 years ago)
• Last Synced: 2024-08-05T20:31:54.922Z (6 months ago)
• Language: Elm
• Size: 2.93 KB
• Stars: 24
• Watchers: 9
• Forks: 1
• Open Issues: 0
• Metadata Files:
  • Readme: readme.md
  • License: license

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README

        
# Node main for Server-side Elm

> Node main for Server-side Elm programs

## Install

There's no installation necessary, this is a boilerplate file that can be used as the entry point for all Server-side or command line based Elm programs.

## Usage

Your final output of your Elm build must be called `elm.js`. This will be loaded via `require` in `main.js`:

```

elm make YourApp.elm --output elm.js

```

Then your main Elm App should be a port module:

```elm

port module YourApp exposing (..)

```

Then your Elm code can initiate a controlled shutdown by writing the exit code to a port called `node`:

```elm

port exitApp : Float -> Cmd msg

```

When it's time to exit, your `update` function can do the following:

```elm

update : Msg -> Model -> ( Model, Cmd Msg )

update msg model =

    case msg of

		SomeEvent ->

			(model, exitApp 1)

```

See `YourApp.elm` code for more usage details.

## SIGINT and SIGTERM

These OS signals will send a message to your program. In the case of the test app, `YourApp.elm`, an `Abort` message is sent. Then the `exitApp` Cmd is returned from `update` with a parameter of -1 which will be returned to the OS.

This approach allows your Elm code to shutdown cleanly and allows you Elm code to always be in control.

## Exit Handlers

Besides the Elm exit handler, it also has a handler for Unhandled Exceptions which returns 1 to the OS. This is useful if you've written or used any badly behaved Javascript code.