Elm-localstorage-ports NPM

Elm LocalStorage Ports

Interface with LocalStorage in Elm.

Quick Start

1. Copy `LocalStorage.elm` into your Elm project

$ npm install -g elm-localstorage-ports
$ cd /path/to/elm/project
$ elm-localstorage-ports init

You will be asked,

Are you inside one of the "source-directories" from your project's elm-package.json? (y/n)

Type y and elm-localstorage-ports will create all of the necessary Elm files.

Note: elm-localstorage-ports init must be run from a directory in the "source-directories\" array in your project's elm-package.json. The above commands assume that /path/to/elm/project is the path containing elm-package.json, and that you have not modified "source-directories".

2. Use it in your Elm code

Example

module MyElmApp.App exposing (main)


import Json.Decode as JD
import Ports.LocalStorage as LocalStorage


type Msg
  = SaveToLocalStorage String
  | LoadFromStorage
  | ReceiveFromLocalStorage (LocalStorage.Key, LocalStorage.Value)


type alias Model =
  { favoriteFruit : String }

  -- ...

subscriptions : Model -> Sub Msg
subscriptions model =
  LocalStorage.storageGetItemResponse ReceiveFromLocalStorage

-- ...

update : Msg -> Model -> (Model, Cmd Msg)
update msg model =
  case msg of
    SaveToLocalStorage fruit ->
      ( { model | favoriteFruit = fruit }
      , LocalStorage.storageSetItem ("favoriteFruit", fruit)
      )

    LoadFromStorage ->
      (model, LocalStorage.storageGetItem "favoriteFruit")

    ReceiveFromLocalStorage ("favoriteFruit", value) ->
      case JD.decodeValue JD.string value of
        Ok fruit ->
          { model | favoriteFruit = fruit } ! []

        Err _ ->
          model ! []

-- ...

3. Register your Elm app in JavaScript

var node = document.getElementById("my-elm-app-container");
var myElmApp = Elm.MyElmApp.embed(node);
var localStoragePorts = require("elm-localstorage-ports");

localStoragePorts.register(myElmApp.ports);