Bump path-parse from 1.0.5 to 1.0.7 in /intro/server

Bumps [path-parse](https://github.com/jbgutierrez/path-parse) from 1.0.5 to 1.0.7.
- [Release notes](https://github.com/jbgutierrez/path-parse/releases)
- [Commits](https://github.com/jbgutierrez/path-parse/commits/v1.0.7)

---
updated-dependencies:
- dependency-name: path-parse
  dependency-type: indirect
...

Signed-off-by: dependabot[bot] <support@github.com>

README.md

@@ -1,4 +1,4 @@
-<i>This workshop is licensed under a <a rel="license" href="http://creativecommons.org/licenses/by/4.0/">Creative Commons Attribution 4.0 International License</a>. The `server/` directories use [`moleculer-node-realworld-example`](https://github.com/gothinkster/moleculer-node-realworld-example-app), which has its own license. The JavaScript interop example uses [`localForage`](https://github.com/localForage/localForage), which is (c) 2013-2017 Mozilla, under the Apache License 2.0. The rest of the code is a variation on [`elm-spa-example`](https://github.com/rtfeldman/elm-spa-example/), an [MIT-licensed](https://github.com/rtfeldman/elm-spa-example/blob/master/LICENSE) implementation of the [`realworld`](https://github.com/gothinkster/realworld) front-end. Many thanks to the authors of these projects!</i>
+<i>This workshop, as well as the slides that go with it (linked below), are all licensed under a <a rel="license" href="http://creativecommons.org/licenses/by/4.0/">Creative Commons Attribution 4.0 International License</a>. The `server/` directories use [`moleculer-node-realworld-example`](https://github.com/gothinkster/moleculer-node-realworld-example-app), which has its own license. The JavaScript interop example uses [`localForage`](https://github.com/localForage/localForage), which is (c) 2013-2017 Mozilla, under the Apache License 2.0. The rest of the code is a variation on [`elm-spa-example`](https://github.com/rtfeldman/elm-spa-example/), an [MIT-licensed](https://github.com/rtfeldman/elm-spa-example/blob/master/LICENSE) implementation of the [`realworld`](https://github.com/gothinkster/realworld) front-end. Many thanks to the authors of these projects!</i>
 
 Getting Started
 ===============
@@ -14,7 +14,7 @@ Getting Started
 > **Note:** Make sure not to run this command with `sudo`! If it gives you an `EACCESS` error, apply [**this fix**](https://docs.npmjs.com/getting-started/fixing-npm-permissions#option-two-change-npms-default-directory) and then re-run the command (still without `sudo`).
 
 ```shell
-npm install -g elm elm-test@elm0.19.0 elm-format
+npm install -g elm elm-test elm-format
 ```
 
 5. Clone this repository
@@ -29,9 +29,9 @@ cd elm-0.19-workshop
 6. Continue with either the [`intro`](https://github.com/rtfeldman/elm-0.19-workshop/blob/master/intro/README.md) or [`advanced`](https://github.com/rtfeldman/elm-0.19-workshop/blob/master/advanced/README.md) instructions, depending on which workshop you're doing!
 
 Video Course of this Workshop
-=======================
+=============================
 
 I recorded full-length videos for [Frontend Masters](https://frontendmasters.com/), in which I teach both of these workshops start to finish:
 
-* [Introduction to Elm](https://frontendmasters.com/courses/intro-elm/) video course
-* [Advanced Elm](https://frontendmasters.com/courses/advanced-elm/) video course
+* [Introduction to Elm](https://frontendmasters.com/courses/intro-elm/) video course ([slides](https://docs.google.com/presentation/d/1LM_W2BRs_ItT-SPDe70C10cbwhGNHGQlJ1fVnAdnRIY/edit?usp=sharing)
+* [Advanced Elm](https://frontendmasters.com/courses/advanced-elm/) video course ([slides](https://docs.google.com/presentation/d/1aFZBXs9kzlZww2JN6iDmrYiQaxKlCAz6a5zpt882GHk/edit?usp=sharing))

TEACHING.md

@@ -15,7 +15,7 @@ some info about it that may be helpful in teaching this workshop.
 
 ## Slides
 
-The [slides](https://docs.google.com/presentation/d/1sNx5k3_fHwJcgm9QEY1LsMH_TyF5SnnOSDKb8HvFsEU/edit?usp=sharing)
+The [slides](https://docs.google.com/presentation/d/1LM_W2BRs_ItT-SPDe70C10cbwhGNHGQlJ1fVnAdnRIY/edit?usp=sharing)
 I use with the workshop include speaker notes. If you’ve seen me give this
 workshop before, you may notice that I’m not following these notes very closely.
 

advanced/README.md

@@ -43,7 +43,12 @@ If things aren’t working, the instructor will be happy to help!
 
 ## Links
 
-* [Elm in Action](https://www.manning.com/books/elm-in-action?a_aid=elm_in_action&a_bid=b15edc5c), a book by [Richard Feldman](https://twitter.com/rtfeldman), creator of this workshop
-* [Official Elm Guide](https://guide.elm-lang.org/) by [Evan Czaplicki](https://twitter.com/czaplic), creator of Elm
-* [Elm Slack](http://elmlang.herokuapp.com/) - amazingly helpful chat community. People in [the `#beginners` channel](https://elmlang.slack.com/messages/C192T0Q1E/) are happy to answer questions!
-* [Elm Discourse](https://discourse.elm-lang.org/) - for longer-form discussions.
+* [The solutions to these exercises](https://github.com/rtfeldman/elm-0.19-workshop/tree/solutions/advanced)
+* [Slides for the Frontend Masters workshop that goes with this repo](https://docs.google.com/presentation/d/1aFZBXs9kzlZww2JN6iDmrYiQaxKlCAz6a5zpt882GHk/edit?usp=sharing)
+* [Advanced Elm Video Course](https://frontendmasters.com/courses/advanced-elm/) that goes with this repo
+* [The Life of a File](https://www.youtube.com/watch?v=XpDsk374LDE) - Evan Czaplicki
+* [The Importance of Ports](https://www.youtube.com/watch?v=P3pL85n9_5s) - Murphy Randle
+* [Working with Maybe](https://www.youtube.com/watch?v=43eM4kNbb6c) - Joël Quenneville
+* [Making Impossible States Impossible](https://www.youtube.com/watch?v=IcgmSRJHu_8) - Richard Feldman
+* [Scaling Elm Apps](https://www.youtube.com/watch?v=DoA4Txr4GUs) - Richard Feldman
+* [Make Data Structures](https://www.youtube.com/watch?v=x1FU3e0sT1I) - Richard Feldman

advanced/part1/elm.json

@@ -3,7 +3,7 @@
     "source-directories": [
         "src"
     ],
-    "elm-version": "0.19.0",
+    "elm-version": "0.19.1",
     "dependencies": {
         "direct": {
             "NoRedInk/elm-json-decode-pipeline": "1.0.0",
@@ -32,4 +32,4 @@
             "elm/random": "1.0.0"
         }
     }
-}
+}

advanced/part1/src/Viewer/Cred.elm

@@ -11,17 +11,18 @@ import Username exposing (Username)
 -- TYPES
 
 
-type Cred
-    = Cred Username String
+type alias Cred =
+    {- 👉 TODO: Make Cred an opaque type, then fix the resulting compiler errors.
+       Afterwards, it should no longer be possible for any other module to access
+       this `token` value directly!
 
-
-
--- INFO
-
-
-username : Cred -> Username
-username (Cred uname _) =
-    uname
+       💡 HINT: Other modules still depend on being able to access the
+       `username` value. Expand this module's API to expose a new way for them
+       to access the `username` without also giving them access to `token`.
+    -}
+    { username : Username
+    , token : String
+    }
 
 
 
@@ -40,14 +41,14 @@ decoder =
 
 
 encodeToken : Cred -> Value
-encodeToken (Cred _ token) =
-    Encode.string token
+encodeToken cred =
+    Encode.string cred.token
 
 
 addHeader : Cred -> RequestBuilder a -> RequestBuilder a
-addHeader (Cred _ token) builder =
+addHeader cred builder =
     builder
-        |> withHeader "authorization" ("Token " ++ token)
+        |> withHeader "authorization" ("Token " ++ cred.token)
 
 
 addHeaderIfAvailable : Maybe Cred -> RequestBuilder a -> RequestBuilder a

advanced/part2/elm.json

@@ -3,7 +3,7 @@
     "source-directories": [
         "src"
     ],
-    "elm-version": "0.19.0",
+    "elm-version": "0.19.1",
     "dependencies": {
         "direct": {
             "NoRedInk/elm-json-decode-pipeline": "1.0.0",
@@ -32,4 +32,4 @@
             "elm/random": "1.0.0"
         }
     }
-}
+}

advanced/part2/src/Article.elm

@@ -159,8 +159,8 @@ slug (Article internals _) =
 
 
 body : Article Full -> Body
-body (Article _ (Full bod)) =
-    bod
+body _ =
+    "👉 TODO make this return the article's body"
 
 
 
@@ -181,8 +181,8 @@ mapAuthor transform (Article info extras) =
 
 
 fromPreview : Body -> Article Preview -> Article Full
-fromPreview bod (Article info _) =
-    Article info (Full bod)
+fromPreview _ _ =
+    "👉 TODO convert from an Article Preview to an Article Full"
 
 
 
@@ -200,7 +200,7 @@ fullDecoder : Maybe Cred -> Decoder (Article Full)
 fullDecoder maybeCred =
     Decode.succeed Article
         |> custom (internalsDecoder maybeCred)
-        |> required "body" (Decode.map Full Body.decoder)
+        |> required "body" "👉 TODO use `Body.decoder` (which is a `Decoder Body`) to decode the body into this Article Full"
 
 
 internalsDecoder : Maybe Cred -> Decoder Internals

advanced/part3/elm.json

@@ -3,7 +3,7 @@
     "source-directories": [
         "src"
     ],
-    "elm-version": "0.19.0",
+    "elm-version": "0.19.1",
     "dependencies": {
         "direct": {
             "NoRedInk/elm-json-decode-pipeline": "1.0.0",
@@ -32,4 +32,4 @@
             "elm/random": "1.0.0"
         }
     }
-}
+}

advanced/part3/src/Page/Article.elm

@@ -71,16 +71,21 @@ init session slug =
       , article = Loading
       }
     , Cmd.batch
+        {- 👉 TODO: Oops! These are all `Task` values, not `Cmd` values!
+
+              Use `|> Task.attempt` and `|> Task.perform` to make this compile.
+
+           Relevant docs:
+
+           https://package.elm-lang.org/packages/elm/core/latest/Task#attempt
+           https://package.elm-lang.org/packages/elm/core/latest/Task#perform
+        -}
         [ Article.fetch maybeCred slug
             |> Http.toTask
-            |> Task.attempt CompletedLoadArticle
         , Comment.list maybeCred slug
             |> Http.toTask
-            |> Task.attempt CompletedLoadComments
         , Time.here
-            |> Task.perform GotTimeZone
         , Loading.slowThreshold
-            |> Task.perform (\_ -> PassedSlowLoadThreshold)
         ]
     )
 

advanced/part4/elm.json

@@ -3,7 +3,7 @@
     "source-directories": [
         "src"
     ],
-    "elm-version": "0.19.0",
+    "elm-version": "0.19.1",
     "dependencies": {
         "direct": {
             "NoRedInk/elm-json-decode-pipeline": "1.0.0",
@@ -32,4 +32,4 @@
             "elm/random": "1.0.0"
         }
     }
-}
+}

advanced/part4/src/Page/Home.elm

@@ -103,7 +103,7 @@ view model =
                             Loaded feed ->
                                 [ div [ class "feed-toggle" ] <|
                                     List.concat
-                                        [ [ viewTabs model.session model.feedTab ]
+                                        [ [ viewTabs model ]
                                         , Feed.viewArticles model.timeZone feed
                                             |> List.map (Html.map GotFeedMsg)
                                         , [ Feed.viewPagination ClickedFeedPage feed ]
@@ -155,16 +155,21 @@ viewBanner =
 -- TABS
 
 
-viewTabs : Session -> FeedTab -> Html Msg
-viewTabs session feedTab =
-    case feedTab of
+{-| 👉 TODO: refactor this to accept narrower types than the entire Model.
+
+    💡 HINT: It may end up with multiple arguments!
+
+-}
+viewTabs : Model -> Html Msg
+viewTabs model =
+    case model.feedTab of
         YourFeed cred ->
             Feed.viewTabs [] (yourFeed cred) [ globalFeed ]
 
         GlobalFeed ->
             let
                 otherTabs =
-                    case Session.cred session of
+                    case Session.cred model.session of
                         Just cred ->
                             [ yourFeed cred ]
 
@@ -176,7 +181,7 @@ viewTabs session feedTab =
         TagFeed tag ->
             let
                 otherTabs =
-                    case Session.cred session of
+                    case Session.cred model.session of
                         Just cred ->
                             [ yourFeed cred, globalFeed ]
 

advanced/part4/src/Page/Profile.elm

@@ -61,21 +61,24 @@ init session username =
     let
         maybeCred =
             Session.cred session
+
+        model =
+            { session = session
+            , timeZone = Time.utc
+            , errors = []
+            , feedTab = defaultFeedTab
+            , feedPage = 1
+            , author = Loading username
+            , feed = Loading username
+            }
     in
-    ( { session = session
-      , timeZone = Time.utc
-      , errors = []
-      , feedTab = defaultFeedTab
-      , feedPage = 1
-      , author = Loading username
-      , feed = Loading username
-      }
+    ( model
     , Cmd.batch
         [ Author.fetch username maybeCred
             |> Http.toTask
             |> Task.mapError (Tuple.pair username)
             |> Task.attempt CompletedAuthorLoad
-        , fetchFeed session username defaultFeedTab 1
+        , fetchFeed model defaultFeedTab 1
         , Task.perform GotTimeZone Time.here
         , Task.perform (\_ -> PassedSlowLoadThreshold) Loading.slowThreshold
         ]
@@ -107,11 +110,19 @@ defaultFeedTab =
 -- HTTP
 
 
-fetchFeed : Session -> Username -> FeedTab -> Int -> Cmd Msg
-fetchFeed session username feedTabs page =
+{-| 👉 TODO: refactor this to accept narrower types than the entire Model.
+
+    💡 HINT: It may end up with multiple arguments!
+
+-}
+fetchFeed : Model -> FeedTab -> Int -> Cmd Msg
+fetchFeed model feedTabs page =
     let
+        username =
+            currentUsername model
+
         maybeCred =
-            Session.cred session
+            Session.cred model.session
 
         ( extraParamName, extraParamVal ) =
             case feedTabs of
@@ -127,7 +138,7 @@ fetchFeed session username feedTabs page =
         |> HttpBuilder.withQueryParam extraParamName extraParamVal
         |> Cred.addHeaderIfAvailable maybeCred
         |> PaginatedList.fromRequestBuilder articlesPerPage page
-        |> Task.map (Feed.init session)
+        |> Task.map (Feed.init model.session)
         |> Task.mapError (Tuple.pair username)
         |> Task.attempt CompletedFeedLoad
 
@@ -340,12 +351,12 @@ update msg model =
 
         ClickedTab tab ->
             ( { model | feedTab = tab }
-            , fetchFeed model.session (currentUsername model) tab 1
+            , fetchFeed model tab 1
             )
 
         ClickedFeedPage page ->
             ( { model | feedPage = page }
-            , fetchFeed model.session (currentUsername model) model.feedTab page
+            , fetchFeed model model.feedTab page
             )
 
         CompletedFollowChange (Ok newAuthor) ->

advanced/part4/src/Page/Settings.elm

@@ -100,7 +100,7 @@ view : Model -> { title : String, content : Html Msg }
 view model =
     let
         form =
-            viewForm (Session.cred model.session) model.form
+            viewForm model
     in
     { title = "Settings"
     , content =
@@ -124,9 +124,16 @@ view model =
     }
 
 
-viewForm : Maybe Cred -> Form -> Html Msg
-viewForm maybeCred form =
-    case maybeCred of
+{-| 👉 TODO refactor this to accept narrower types than the entire Model.
+💡 HINT: It may end up with multiple arguments!
+-}
+viewForm : Model -> Html Msg
+viewForm model =
+    let
+        form =
+            model.form
+    in
+    case Session.cred model.session of
         Nothing ->
             text ""
 

advanced/part5/elm-package.json

@@ -1,15 +0,0 @@
-{
-    "version": "1.0.0",
-    "summary": "helpful summary of your project, less than 80 characters",
-    "repository": "https://github.com/user/project.git",
-    "license": "BSD3",
-    "source-directories": [
-        "."
-    ],
-    "exposed-modules": [],
-    "dependencies": {
-        "elm-lang/core": "5.1.1 <= v < 6.0.0",
-        "elm-lang/html": "2.0.0 <= v < 3.0.0"
-    },
-    "elm-version": "0.18.0 <= v < 0.19.0"
-}

advanced/part5/elm.json

@@ -3,7 +3,7 @@
     "source-directories": [
         "src"
     ],
-    "elm-version": "0.19.0",
+    "elm-version": "0.19.1",
     "dependencies": {
         "direct": {
             "NoRedInk/elm-json-decode-pipeline": "1.0.0",
@@ -32,4 +32,4 @@
             "elm/random": "1.0.0"
         }
     }
-}
+}

advanced/part5/src/Page/Home.elm

@@ -109,7 +109,7 @@ view model =
                                           ]
                                         , Feed.viewArticles model.timeZone feed
                                             |> List.map (Html.map GotFeedMsg)
-                                        , [ PaginatedList.view ClickedFeedPage (Feed.articles feed) ]
+                                        , [ viewPagination (Feed.articles feed) ]
                                         ]
                                 ]
 
@@ -155,6 +155,46 @@ viewBanner =
 
 
 
+-- PAGINATION
+
+
+{-| 👉 TODO: Relocate `viewPagination` into `PaginatedList.view` and make it reusable,
+then refactor both Page.Home and Page.Profile to use it!
+
+💡 HINT: Make `PaginatedList.view` return `Html msg` instead of `Html Msg`.
+(You'll need to introduce at least one extra argument for this to work.)
+
+-}
+viewPagination : PaginatedList (Article Preview) -> Html Msg
+viewPagination list =
+    let
+        viewPageLink currentPage =
+            pageLink currentPage (currentPage == page list)
+    in
+    if total list > 1 then
+        List.range 1 (total list)
+            |> List.map viewPageLink
+            |> ul [ class "pagination" ]
+
+    else
+        Html.text ""
+
+
+pageLink : Int -> Bool -> Html Msg
+pageLink targetPage isActive =
+    li [ classList [ ( "page-item", True ), ( "active", isActive ) ] ]
+        [ a
+            [ class "page-link"
+            , onClick (ClickedFeedPage targetPage)
+
+            -- The RealWorld CSS requires an href to work properly.
+            , href ""
+            ]
+            [ text (String.fromInt targetPage) ]
+        ]
+
+
+
 -- TABS
 
 

advanced/part5/src/Page/Profile.elm

@@ -218,7 +218,7 @@ view model =
                                                 [ [ viewTabs model.feedTab ]
                                                 , Feed.viewArticles model.timeZone feed
                                                     |> List.map (Html.map GotFeedMsg)
-                                                , [ PaginatedList.view ClickedFeedPage (Feed.articles feed) ]
+                                                , [ viewPagination (Feed.articles feed) ]
                                                 ]
                                         ]
                                     ]
@@ -246,6 +246,46 @@ view model =
 
 
 
+-- PAGINATION
+
+
+{-| 👉 TODO: Relocate `viewPagination` into `PaginatedList.view` and make it reusable,
+then refactor both Page.Home and Page.Profile to use it!
+
+💡 HINT: Make `PaginatedList.view` return `Html msg` instead of `Html Msg`.
+(You'll need to introduce at least one extra argument for this to work.)
+
+-}
+viewPagination : PaginatedList (Article Preview) -> Html Msg
+viewPagination list =
+    let
+        viewPageLink currentPage =
+            pageLink currentPage (currentPage == page list)
+    in
+    if total list > 1 then
+        List.range 1 (total list)
+            |> List.map viewPageLink
+            |> ul [ class "pagination" ]
+
+    else
+        Html.text ""
+
+
+pageLink : Int -> Bool -> Html Msg
+pageLink targetPage isActive =
+    li [ classList [ ( "page-item", True ), ( "active", isActive ) ] ]
+        [ a
+            [ class "page-link"
+            , onClick (ClickedFeedPage targetPage)
+
+            -- The RealWorld CSS requires an href to work properly.
+            , href ""
+            ]
+            [ text (String.fromInt targetPage) ]
+        ]
+
+
+
 -- PAGE TITLE
 
 

advanced/part5/src/PaginatedList.elm

@@ -1,6 +1,5 @@
-module PaginatedList exposing (PaginatedList, fromList, fromRequestBuilder, map, page, total, values, view)
+module PaginatedList exposing (PaginatedList, fromList, fromRequestBuilder, map, page, total, values)
 
-import Article exposing (Article, Preview)
 import Html exposing (Html, a, li, text, ul)
 import Html.Attributes exposing (class, classList, href)
 import Html.Events exposing (onClick)
@@ -88,32 +87,3 @@ fromRequestBuilder resultsPerPage pageNumber builder =
 
 
 -- VIEW
-
-
-view : (Int -> msg) -> PaginatedList (Article Preview) -> Html msg
-view toMsg list =
-    let
-        viewPageLink currentPage =
-            pageLink toMsg currentPage (currentPage == page list)
-    in
-    if total list > 1 then
-        List.range 1 (total list)
-            |> List.map viewPageLink
-            |> ul [ class "pagination" ]
-
-    else
-        Html.text ""
-
-
-pageLink : (Int -> msg) -> Int -> Bool -> Html msg
-pageLink toMsg targetPage isActive =
-    li [ classList [ ( "page-item", True ), ( "active", isActive ) ] ]
-        [ a
-            [ class "page-link"
-            , onClick (toMsg targetPage)
-
-            -- The RealWorld CSS requires an href to work properly.
-            , href ""
-            ]
-            [ text (String.fromInt targetPage) ]
-        ]

advanced/part6/elm.json

@@ -3,7 +3,7 @@
     "source-directories": [
         "src"
     ],
-    "elm-version": "0.19.0",
+    "elm-version": "0.19.1",
     "dependencies": {
         "direct": {
             "NoRedInk/elm-json-decode-pipeline": "1.0.0",
@@ -32,4 +32,4 @@
             "elm/random": "1.0.0"
         }
     }
-}
+}

advanced/part6/src/Page/Home.elm

@@ -155,27 +155,46 @@ viewBanner =
 -- TABS
 
 
+{-| TODO: Have viewTabs render all the tabs, using `activeTab` as the
+single source of truth for their state.
+
+    The specification for how the tabs work is:
+
+    1. If the user is logged in, render `yourFeed` as the first tab. Examples:
+
+    "Your Feed"    "Global Feed"
+    "Your Feed"    "Global Feed"  "#dragons"
+
+    2. If the user is NOT logged in, do not render `yourFeed` at all. Examples:
+
+    "Global Feed"
+    "Global Feed"  "#dragons"
+
+    3. If the active tab is a `TagFeed`, render that tab last. Show the tag it contains with a "#" in front.
+
+    "Global Feed"  "#dragons"
+    "Your Feed"    "Global Feed"  "#dragons"
+
+    3. If the active tab is NOT a `TagFeed`, do not render a tag tab at all.
+
+    "Your Feed"    "Global Feed"
+    "Global Feed"
+
+    💡 HINT: The 4 declarations after `viewTabs` may be helpful!
+
+-}
 viewTabs : Bool -> FeedTab -> Html Msg
 viewTabs isLoggedIn activeTab =
     ul [ class "nav nav-pills outline-active" ] <|
-        List.singleton <|
-            case activeTab of
-                YourFeed ->
-                    tabBar [] yourFeed [ globalFeed ]
+        case activeTab of
+            YourFeed ->
+                []
 
-                GlobalFeed ->
-                    if isLoggedIn then
-                        tabBar [ yourFeed ] globalFeed []
+            GlobalFeed ->
+                []
 
-                    else
-                        tabBar [] globalFeed []
-
-                TagFeed tagName ->
-                    if isLoggedIn then
-                        tabBar [ yourFeed, globalFeed ] (tagFeed tagName) []
-
-                    else
-                        tabBar [ globalFeed ] (tagFeed tagName) []
+            TagFeed tagName ->
+                []
 
 
 tabBar :

advanced/part7/elm.json

@@ -3,7 +3,7 @@
     "source-directories": [
         "src"
     ],
-    "elm-version": "0.19.0",
+    "elm-version": "0.19.1",
     "dependencies": {
         "direct": {
             "NoRedInk/elm-json-decode-pipeline": "1.0.0",
@@ -32,4 +32,4 @@
             "elm/random": "1.0.0"
         }
     }
-}
+}

advanced/part7/src/Author.elm

@@ -206,14 +206,17 @@ toggleFollowButton txt extraClasses msgWhenClicked uname =
 
 decoder : Maybe Cred -> Decoder Author
 decoder maybeCred =
-    Decode.succeed Tuple.pair
+    {- 👉 TODO: Use this `Profile` and `Username` to decode an `Author`!
+
+       💡 HINT: `decoderHelp` will help here, but slightly altering its type may make things easier...
+    -}
+    Decode.succeed "..."
         |> custom Profile.decoder
         |> required "username" Username.decoder
-        |> Decode.andThen (decoderHelp maybeCred)
 
 
-decoderHelp : Maybe Cred -> ( Profile, Username ) -> Decoder Author
-decoderHelp maybeCred ( prof, uname ) =
+decoderHelp : Maybe Cred -> Profile -> Username -> Decoder Author
+decoderHelp maybeCred prof uname =
     case maybeCred of
         Nothing ->
             -- If you're logged out, you can't be following anyone!

advanced/part7/src/Timestamp.elm

@@ -24,18 +24,17 @@ view timeZone timestamp =
 -}
 iso8601Decoder : Decoder Time.Posix
 iso8601Decoder =
-    Decode.string
-        |> Decode.andThen decoderHelp
+    {- 👉 TODO: Use the following function to decode this Time.Posix value:
 
 
-decoderHelp : String -> Decoder Time.Posix
-decoderHelp str =
-    case Iso8601.toTime str of
-        Ok time ->
-            Decode.succeed time
+       Iso8601.toTime : String -> Result (List DeadEnd) Time.Posix
 
-        Err _ ->
-            Decode.fail ("Invalid ISO-8601 timestamp: " ++ str)
+
+       ❕ NOTE: You can disregard the (List DeadEnd) here. No need to use it to complete this exercise!
+
+       💡 HINT: Decode.andThen will be useful here.
+    -}
+    "..."
 
 
 

advanced/part8/elm-package.json

@@ -1,15 +0,0 @@
-{
-    "version": "1.0.0",
-    "summary": "helpful summary of your project, less than 80 characters",
-    "repository": "https://github.com/user/project.git",
-    "license": "BSD3",
-    "source-directories": [
-        "."
-    ],
-    "exposed-modules": [],
-    "dependencies": {
-        "elm-lang/core": "5.1.1 <= v < 6.0.0",
-        "elm-lang/html": "2.0.0 <= v < 3.0.0"
-    },
-    "elm-version": "0.18.0 <= v < 0.19.0"
-}

advanced/part8/elm.json

@@ -3,7 +3,7 @@
     "source-directories": [
         "src"
     ],
-    "elm-version": "0.19.0",
+    "elm-version": "0.19.1",
     "dependencies": {
         "direct": {
             "NoRedInk/elm-json-decode-pipeline": "1.0.0",
@@ -32,4 +32,4 @@
             "elm/random": "1.0.0"
         }
     }
-}
+}

advanced/part8/src/Route.elm

@@ -34,11 +34,14 @@ parser =
         , Parser.map Login (s "login")
         , Parser.map Logout (s "logout")
         , Parser.map Profile (s "profile" </> Username.urlParser)
-        , Parser.map Settings (s "settings")
-        , Parser.map Register (s "settings")
-        , Parser.map Article (s "article" </> Slug.urlParser)
-        , Parser.map EditArticle (s "editor" </> Slug.urlParser)
-        , Parser.map NewArticle (s "editor")
+
+        -- 👉 TODO /settings       →  Settings
+        -- 👉 TODO /register       →  Register
+        -- 👉 TODO /article/[slug] →  Article [slug]
+        -- 👉 TODO /editor         →  NewArticle
+        -- 👉 TODO /editor/[slug]  →  EditArticle [slug]
+        --
+        -- 💡 HINT: Article and EditArticle work similarly to how Profile works.
         ]
 
 

advanced/server/elm.json

@@ -3,10 +3,10 @@
     "source-directories": [
         "src"
     ],
-    "elm-version": "0.19.0",
+    "elm-version": "0.19.1",
     "dependencies": {
         "direct": {
-            "NoRedInk/json-decode-pipeline": "1.0.0",
+            "NoRedInk/elm-json-decode-pipeline": "1.0.0",
             "elm/browser": "1.0.0",
             "elm/core": "1.0.0",
             "elm/html": "1.0.0",
@@ -16,7 +16,7 @@
             "elm/url": "1.0.0",
             "elm-explorations/markdown": "1.0.0",
             "lukewestby/elm-http-builder": "6.0.0",
-            "rtfeldman/elm-iso8601": "1.0.1",
+            "rtfeldman/elm-iso8601-date-strings": "1.0.0",
             "rtfeldman/elm-validate": "4.0.0"
         },
         "indirect": {

intro/README.md

@@ -1,7 +1,7 @@
 Introduction to Elm Workshop
 ============================
 
-If you haven't already, follow the [Getting Started instructions](https://github.com/rtfeldman/elm-0.19-workshop/blob/master/intro/README.md
+If you haven't already, follow the [Getting Started instructions](https://github.com/rtfeldman/elm-0.19-workshop#getting-started
 ) at the root of this repository, then continue here!
 
 ## Start the server
@@ -24,7 +24,7 @@ of the workshop, so **don't close it** until the workshop is over!
 
 Leave the existing terminal running, and open a **second** terminal.
 
-In the new termnal, `cd` into the `elm-0.19-workshop/intro/server/` directory again.
+In the new terminal, `cd` into the `elm-0.19-workshop/intro/server/` directory again.
 
 Then run this to build the Elm code for the first time:
 
@@ -43,6 +43,9 @@ If things aren’t working, the instructor will be happy to help!
 
 ## Links
 
+* [The solutions to these exercises](https://github.com/rtfeldman/elm-0.19-workshop/tree/solutions/intro)
+* [Slides for the Frontend Masters video course that goes with this repo](https://docs.google.com/presentation/d/1LM_W2BRs_ItT-SPDe70C10cbwhGNHGQlJ1fVnAdnRIY/edit?usp=sharing)
+* [Introduction to Elm Video Course](https://frontendmasters.com/courses/intro-elm/) that goes along with this repo.
 * [Elm in Action](https://www.manning.com/books/elm-in-action?a_aid=elm_in_action&a_bid=b15edc5c), a book by [Richard Feldman](https://twitter.com/rtfeldman), creator of this workshop
 * [Official Elm Guide](https://guide.elm-lang.org/) by [Evan Czaplicki](https://twitter.com/czaplic), creator of Elm
 * [Elm Slack](http://elmlang.herokuapp.com/) - amazingly helpful chat community. People in [the `#beginners` channel](https://elmlang.slack.com/messages/C192T0Q1E/) are happy to answer questions!

intro/part1/Main.elm

@@ -5,11 +5,25 @@ import Html.Attributes exposing (..)
 
 
 banner =
+    {- 👉 TODO: Add a logo and tagline to this banner, so its structure becomes:
+
+          <div class="banner">
+              <div class="container">
+
+                  <h1 class="logo-font">conduit</h1>
+
+                  <p>A place to share your knowledge.</p>
+
+               </div>
+          </div>
+
+       💡 HINT 1: the <div class="container"> above is an element with 2 child nodes.
+
+       💡 HINT 2: the <div class="feed-toggle"> below is an element with text.
+    -}
     div [ class "banner" ]
         [ div [ class "container" ]
-            [ h1 [ class "logo-font" ] [ text "conduit" ]
-            , p [] [ text "A place to share your knowledge." ]
-            ]
+            [ text "👉 TODO: Put the <h1> here instead of this text, then add the <p> right after the <h1>" ]
         ]
 
 
@@ -19,7 +33,7 @@ feed =
 
 main =
     div [ class "home-page" ]
-        [ banner
+        [ div [] [ text "👉 TODO: Replace this <div> with the banner" ]
         , div [ class "container page" ]
             [ div [ class "row" ]
                 [ div [ class "col-md-9" ] [ feed ]

intro/part1/elm.json

@@ -3,7 +3,7 @@
     "source-directories": [
         "."
     ],
-    "elm-version": "0.19.0",
+    "elm-version": "0.19.1",
     "dependencies": {
         "direct": {
             "elm/core": "1.0.0",

intro/part2/elm.json

@@ -3,7 +3,7 @@
     "source-directories": [
         "src"
     ],
-    "elm-version": "0.19.0",
+    "elm-version": "0.19.1",
     "dependencies": {
         "direct": {
             "elm/core": "1.0.0",

intro/part2/src/Main.elm

@@ -7,13 +7,18 @@ import Html.Attributes exposing (..)
 viewTags tags =
     let
         renderedTags =
-            List.map viewTag tags
+            -- 👉 TODO: use `List.map` and `viewTag` to render the tags
+            []
     in
     div [ class "tag-list" ] renderedTags
 
 
 viewTag tagName =
-    button [ class "tag-pill tag-default" ] [ text tagName ]
+    {- 👉 TODO: render something like this:
+
+       <button class="tag-pill tag-default">tag name goes here</button>
+    -}
+    button [] []
 
 
 main =
@@ -29,7 +34,9 @@ main =
                 , div [ class "col-md-3" ]
                     [ div [ class "sidebar" ]
                         [ p [] [ text "Popular Tags" ]
-                        , viewTags tags
+
+                        -- 👉 TODO: instead of passing [] to viewTags, pass the actual tags
+                        , viewTags []
                         ]
                     ]
                 ]

intro/part3/elm.json

@@ -3,18 +3,16 @@
     "source-directories": [
         "src"
     ],
-    "elm-version": "0.19.0",
+    "elm-version": "0.19.1",
     "dependencies": {
         "direct": {
-            "elm/browser": "1.0.0",
             "elm/core": "1.0.0",
             "elm/html": "1.0.0"
         },
         "indirect": {
             "elm/json": "1.0.0",
             "elm/time": "1.0.0",
-            "elm/url": "1.0.0",
-            "elm/virtual-dom": "1.0.0"
+            "elm/url": "1.0.0"
         }
     },
     "test-dependencies": {

intro/part3/src/Main.elm

@@ -1,5 +1,8 @@
 module Main exposing (main)
 
+-- NOTE: Make sure to follow the instructions in the README for part3
+-- to install the elm/browser package before running elm make!
+--
 -- FYI: 👇 You can see our new `Article` module in `src/Article.elm`
 
 import Article
@@ -25,11 +28,15 @@ initialModel =
 
 
 update msg model =
-    if msg.description == "ClickedTag" then
-        { model | selectedTag = msg.data }
+    {- 👉 TODO: If `msg.description` is "ClickedTag", then
+                set the model's `selectedTag` field to be `msg.data`
 
-    else
-        model
+       💡 HINT: record update syntax looks like this:
+
+                { model | foo = bar }
+
+    -}
+    model
 
 
 
@@ -38,8 +45,16 @@ update msg model =
 
 view model =
     let
+        {- 👉 TODO: Filter the articles down to only the ones
+                    that include the currently selected tag.
+
+           💡 HINT: Replace `True` below with something involving
+                    `List.member`, `article.tags`, and `model.selectedTag`
+
+                    Docs for List.member: http://package.elm-lang.org/packages/elm-lang/core/latest/List#member
+        -}
         articles =
-            List.filter (\article -> List.member model.selectedTag article.tags)
+            List.filter (\article -> True)
                 model.allArticles
 
         feed =
@@ -89,7 +104,17 @@ viewTag selectedTagName tagName =
     in
     button
         [ class ("tag-pill " ++ otherClass)
-        , onClick { description = "ClickedTag", data = tagName }
+
+        {- 👉 TODO: Add an `onClick` handler which sends a msg
+                    that our `update` function above will use
+                    to set the currently selected tag to `tagName`.
+
+           💡 HINT: It should look something like this:
+
+                    , onClick { description = … , data = … }
+
+                    👆 Don't forget to add a comma before `onClick`!
+        -}
         ]
         [ text tagName ]
 

intro/part4/elm-package.json

@@ -1,15 +0,0 @@
-{
-    "version": "1.0.0",
-    "summary": "helpful summary of your project, less than 80 characters",
-    "repository": "https://github.com/user/project.git",
-    "license": "BSD3",
-    "source-directories": [
-        "."
-    ],
-    "exposed-modules": [],
-    "dependencies": {
-        "elm-lang/core": "5.1.1 <= v < 6.0.0",
-        "elm-lang/html": "2.0.0 <= v < 3.0.0"
-    },
-    "elm-version": "0.18.0 <= v < 0.19.0"
-}

intro/part4/elm.json

@@ -3,7 +3,7 @@
     "source-directories": [
         "src"
     ],
-    "elm-version": "0.19.0",
+    "elm-version": "0.19.1",
     "dependencies": {
         "direct": {
             "elm/browser": "1.0.0",
@@ -21,4 +21,4 @@
         "direct": {},
         "indirect": {}
     }
-}
+}

intro/part4/src/Main.elm

@@ -14,20 +14,27 @@ import Html.Events exposing (onClick)
 type alias Model =
     { tags : List String
     , selectedTag : String
-    , allArticles : List Article
+
+    {- 👉 TODO: change this `allArticles` annotation to the following:
+
+        allArticles : List Article
+
+
+       💡 HINT: You'll need to move the existing annotation to a `type alias`.
+    -}
+    , allArticles :
+        List
+            { title : String
+            , description : String
+            , body : String
+            , tags : List String
+            , slug : String
+            }
     }
 
 
-type alias Article =
-    { title : String
-    , description : String
-    , body : String
-    , tags : List String
-    , slug : String
-    }
-
-
-initialModel : Model
+{-| 👉 TODO: Replace this comment with a type annotation for `initialModel`
+-}
 initialModel =
     { tags = Article.tags
     , selectedTag = "elm"
@@ -45,7 +52,8 @@ type alias Msg =
     }
 
 
-update : Msg -> Model -> Model
+{-| 👉 TODO: Replace this comment with a type annotation for `update`
+-}
 update msg model =
     if msg.description == "ClickedTag" then
         { model | selectedTag = msg.data }
@@ -58,7 +66,8 @@ update msg model =
 -- VIEW
 
 
-view : Model -> Html Msg
+{-| 👉 TODO: Replace this comment with a type annotation for `view`
+-}
 view model =
     let
         articles =
@@ -84,7 +93,8 @@ view model =
         ]
 
 
-viewArticle : Article -> Html Msg
+{-| 👉 TODO: Replace this comment with a type annotation for `viewArticle`
+-}
 viewArticle article =
     div [ class "article-preview" ]
         [ h1 [] [ text article.title ]
@@ -93,7 +103,8 @@ viewArticle article =
         ]
 
 
-viewBanner : Html Msg
+{-| 👉 TODO: Replace this comment with a type annotation for `viewBanner`
+-}
 viewBanner =
     div [ class "banner" ]
         [ div [ class "container" ]
@@ -103,7 +114,8 @@ viewBanner =
         ]
 
 
-viewTag : String -> String -> Html Msg
+{-| 👉 TODO: Replace this comment with a type annotation for `viewTag`
+-}
 viewTag selectedTagName tagName =
     let
         otherClass =

intro/part5/elm.json

@@ -3,7 +3,7 @@
     "source-directories": [
         "src"
     ],
-    "elm-version": "0.19.0",
+    "elm-version": "0.19.1",
     "dependencies": {
         "direct": {
             "NoRedInk/elm-json-decode-pipeline": "1.0.0",
@@ -32,4 +32,4 @@
             "elm/random": "1.0.0"
         }
     }
-}
+}

intro/part5/src/Page/Register.elm

@@ -86,7 +86,11 @@ viewForm form =
             [ input
                 [ class "form-control form-control-lg"
                 , placeholder "Username"
-                , onInput EnteredUsername
+
+                {- 👉 TODO: when the user inputs a username, update it in the Model.
+
+                   💡 HINT: Look at how the Email input below does this. 👇
+                -}
                 , value form.username
                 ]
                 []
@@ -137,7 +141,6 @@ type Msg
     = SubmittedForm
     | EnteredEmail String
     | EnteredPassword String
-    | EnteredUsername String
     | CompletedRegister (Result Http.Error Viewer)
     | GotSession Session
 
@@ -151,9 +154,6 @@ update msg model =
         EnteredPassword password ->
             updateForm (\form -> { form | password = password }) model
 
-        EnteredUsername username ->
-            updateForm (\form -> { form | username = username }) model
-
         SubmittedForm ->
             case validate model.form of
                 Ok validForm ->

intro/part6/elm.json

@@ -3,7 +3,7 @@
     "source-directories": [
         "src"
     ],
-    "elm-version": "0.19.0",
+    "elm-version": "0.19.1",
     "dependencies": {
         "direct": {
             "NoRedInk/elm-json-decode-pipeline": "1.0.0",

intro/part6/src/Avatar.elm

@@ -40,12 +40,12 @@ src (Avatar maybeUrl) =
 
 resolveAvatarUrl : Maybe String -> String
 resolveAvatarUrl maybeUrl =
-    case maybeUrl of
-        Just url ->
-            url
+    {- 👉 TODO #1 of 2: return the user's avatar from maybeUrl, if maybeUrl actually
+       contains one. If maybeUrl is Nothing, return this URL instead:
 
-        Nothing ->
-            "https://static.productionready.io/images/smiley-cyrus.jpg"
+          https://static.productionready.io/images/smiley-cyrus.jpg
+    -}
+    ""
 
 
 encode : Avatar -> Value

intro/part6/src/Page/Article/Editor.elm

@@ -572,7 +572,6 @@ toTagList tagString =
     -}
     String.split " " tagString
         |> List.map String.trim
-        |> List.filter (\str -> str /= "")
 
 
 edit : Slug -> TrimmedForm -> Cred -> Http.Request (Article Full)

intro/part7/elm.json

@@ -3,7 +3,7 @@
     "source-directories": [
         "src"
     ],
-    "elm-version": "0.19.0",
+    "elm-version": "0.19.1",
     "dependencies": {
         "direct": {
             "NoRedInk/elm-json-decode-pipeline": "1.0.0",

intro/part7/src/Article.elm

@@ -182,12 +182,26 @@ type alias Metadata =
 
 metadataDecoder : Decoder Metadata
 metadataDecoder =
+    {- 👉 TODO: replace the calls to `hardcoded` with calls to `required`
+          in order to decode these fields:
+
+       --- "description" -------> description : String
+       --- "title" -------------> title : String
+       --- "tagList" -----------> tags : List String
+       --- "favorited" ---------> favorited : Bool
+       --- "favoritesCount" ----> favoritesCount : Int
+
+       Once this is done, the articles in the feed should look normal again.
+
+       💡 HINT: Order matters! These must be decoded in the same order
+       as the order of the fields in `type alias Metadata` above. ☝️
+    -}
     Decode.succeed Metadata
-        |> required "description" string
-        |> required "title" string
-        |> required "tagList" (list string)
-        |> required "favorited" bool
-        |> required "favoritesCount" int
+        |> hardcoded "(needs decoding!)"
+        |> hardcoded "(needs decoding!)"
+        |> hardcoded []
+        |> hardcoded False
+        |> hardcoded 0
         |> required "createdAt" Timestamp.iso8601Decoder
 
 

intro/part8/README.md

@@ -12,6 +12,6 @@ Then open `http://localhost:3000` in your browser.
 
 ## Exercise
 
-We need to make login work. Currently it doesn't actually send a HTTP request to the server.
+We need to make signup work again. Currently it doesn't actually send a HTTP request to the server.
 
-We'll fix this by editing `src/Page/Login.elm` and resolving the TODOs there.
+We'll fix this by editing `src/Page/Register.elm` and resolving the TODOs there.

intro/part8/elm.json

@@ -3,7 +3,7 @@
     "source-directories": [
         "src"
     ],
-    "elm-version": "0.19.0",
+    "elm-version": "0.19.1",
     "dependencies": {
         "direct": {
             "NoRedInk/elm-json-decode-pipeline": "1.0.0",

intro/part8/src/Page/Register.elm

@@ -155,13 +155,34 @@ update msg model =
                 responseDecoder =
                     Decode.field "user" Viewer.decoder
 
+                {- 👉 TODO: Create a Http.Request value that represents
+                      a POST request to "/api/users"
+
+                   💡 HINT 1: Documentation for `Http.post` is here:
+
+                       http://package.elm-lang.org/packages/elm-lang/http/1.0.0/Http#post
+
+                   💡 HINT 2: Look at the values defined above in this
+                   let-expression. What are their types? What are the types the
+                   `Http.post` function is looking for?
+                -}
                 request : Http.Request Viewer
                 request =
-                    Http.post "/api/users" requestBody responseDecoder
+                    Debug.todo "Call Http.post to represent a POST to /api/users"
 
+                {- 👉 TODO: Use Http.send to turn the request we just defined
+                   into a Cmd for `update` to execute.
+
+                   💡 HINT 1: Documentation for `Http.send` is here:
+
+                    http://package.elm-lang.org/packages/elm-lang/http/1.0.0/Http#send
+
+                   💡 HINT 2: The `CompletedRegister` variant defined in `type Msg`
+                    will be useful here!
+                -}
                 cmd : Cmd Msg
                 cmd =
-                    Http.send CompletedRegister request
+                    Cmd.none
             in
             ( { model | problems = [] }, cmd )
 

intro/part9/README.md

@@ -1,8 +1,8 @@
-# Part 8
+# Part 9
 
 Once again, we'll be building `src/Main.elm`, but editing a different file.
 
-To build everything, `cd` into the `part8/` directory and run8
+To build everything, `cd` into the `part9/` directory and run:
 
 ```shell
 elm make src/Main.elm --output ../server/public/elm.js

intro/part9/elm.json

@@ -3,10 +3,10 @@
     "source-directories": [
         "src"
     ],
-    "elm-version": "0.19.0",
+    "elm-version": "0.19.1",
     "dependencies": {
         "direct": {
-            "NoRedInk/json-decode-pipeline": "1.0.0",
+            "NoRedInk/elm-json-decode-pipeline": "1.0.0",
             "elm/browser": "1.0.0",
             "elm/core": "1.0.0",
             "elm/html": "1.0.0",
@@ -16,7 +16,7 @@
             "elm/url": "1.0.0",
             "elm-explorations/markdown": "1.0.0",
             "lukewestby/elm-http-builder": "6.0.0",
-            "rtfeldman/elm-iso8601": "1.0.1"
+            "rtfeldman/elm-iso8601-date-strings": "1.0.0"
         },
         "indirect": {
             "elm/parser": "1.0.0",

intro/part9/src/Article.elm

@@ -40,7 +40,7 @@ import Html.Attributes exposing (class)
 import Html.Events exposing (stopPropagationOn)
 import Http
 import HttpBuilder exposing (RequestBuilder, withBody, withExpect, withQueryParams)
-import Json.Decode as Decode exposing (Decoder, bool, int, list, string)
+import Json.Decode as Decode exposing (Decoder)
 import Json.Decode.Pipeline exposing (custom, hardcoded, required)
 import Json.Encode as Encode
 import Markdown
@@ -83,6 +83,47 @@ type Article a
     = Article Internals a
 
 
+{-| Metadata about the article - its title, description, and so on.
+
+Importantly, this module's public API exposes a way to read this metadata, but
+not to alter it. This is read-only information!
+
+If we find ourselves using any particular piece of metadata often,
+for example `title`, we could expose a convenience function like this:
+
+Article.title : Article a -> String
+
+If you like, it's totally reasonable to expose a function like that for every one
+of these fields!
+
+(Okay, to be completely honest, exposing one function per field is how I prefer
+to do it, and that's how I originally wrote this module. However, I'm aware that
+this code base has become a common reference point for beginners, and I think it
+is _extremely important_ that slapping some "getters and setters" on a record
+does not become a habit for anyone who is getting started with Elm. The whole
+point of making the Article type opaque is to create guarantees through
+_selectively choosing boundaries_ around it. If you aren't selective about
+where those boundaries are, and instead expose a "getter and setter" for every
+field in the record, the result is an API with no more guarantees than if you'd
+exposed the entire record directly! It is so important to me that beginners not
+fall into the terrible "getters and setters" trap that I've exposed this
+Metadata record instead of exposing a single function for each of its fields,
+as I did originally. This record is not a bad way to do it, by any means,
+but if this seems at odds with <https://youtu.be/x1FU3e0sT1I> - now you know why!
+See commit c2640ae3abd60262cdaafe6adee3f41d84cd85c3 for how it looked before.
+)
+
+-}
+type alias Metadata =
+    { description : String
+    , title : String
+    , tags : List String
+    , createdAt : Time.Posix
+    , favorited : Bool
+    , favoritesCount : Int
+    }
+
+
 type alias Internals =
     { slug : Slug
     , author : Author
@@ -170,39 +211,15 @@ internalsDecoder maybeCred =
         |> custom metadataDecoder
 
 
-type alias Metadata =
-    { description : String
-    , title : String
-    , tags : List String
-    , favorited : Bool
-    , favoritesCount : Int
-    , createdAt : Time.Posix
-    }
-
-
 metadataDecoder : Decoder Metadata
 metadataDecoder =
-    {- 👉 TODO: replace the calls to `hardcoded` with calls to `required`
-          in order to decode these fields:
-
-       --- "description" -------> description : String
-       --- "title" -------------> title : String
-       --- "tagList" -----------> tags : List String
-       --- "favorited" ---------> favorited : Bool
-       --- "favoritesCount" ----> favoritesCount : Int
-
-       Once this is done, the articles in the feed should look normal again.
-
-       💡 HINT: Order matters! These must be decoded in the same order
-       as the order of the fields in `type alias Metadata` above. ☝️
-    -}
     Decode.succeed Metadata
-        |> hardcoded "(needs decoding!)"
-        |> hardcoded "(needs decoding!)"
-        |> hardcoded []
-        |> hardcoded False
-        |> hardcoded 0
+        |> required "description" (Decode.map (Maybe.withDefault "") (Decode.nullable Decode.string))
+        |> required "title" Decode.string
+        |> required "tagList" (Decode.list Decode.string)
         |> required "createdAt" Timestamp.iso8601Decoder
+        |> required "favorited" Decode.bool
+        |> required "favoritesCount" Decode.int
 
 
 

intro/part9/src/Session.elm

@@ -72,7 +72,7 @@ login newViewer =
     Viewer.encode newViewer
         |> Encode.encode 0
         |> Just
-        |> storeSession
+        |> sendSessionToJavaScript
 
 
 
@@ -81,10 +81,24 @@ login newViewer =
 
 logout : Cmd msg
 logout =
-    storeSession Nothing
+    sendSessionToJavaScript Nothing
 
 
-port storeSession : Maybe String -> Cmd msg
+{-| 👉 TODO 1 of 2: Replace this do-nothing function with a port that sends the
+authentication token to JavaScript.
+
+    💡 HINT 1: When you convert it to a port, the port's name _must_ match
+    the name JavaScript expects in `intro/server/public/index.html`.
+    That name is not `sendSessionToJavaScript`, so you will need to
+    rename it to match what JS expects!
+
+    💡 HINT 2: After you rename it, some code in this file will break because
+    it was depending on the old name. Follow the compiler errors to fix them!
+
+-}
+sendSessionToJavaScript : Maybe String -> Cmd msg
+sendSessionToJavaScript maybeAuthenticationToken =
+    Cmd.none
 
 
 
@@ -93,10 +107,24 @@ port storeSession : Maybe String -> Cmd msg
 
 changes : (Session -> msg) -> Nav.Key -> Sub msg
 changes toMsg key =
-    onSessionChange (\val -> toMsg (decode key val))
+    receiveSessionFromJavaScript (\val -> toMsg (decode key val))
 
 
-port onSessionChange : (Value -> msg) -> Sub msg
+{-| 👉 TODO 2 of 2: Replace this do-nothing function with a port that receives the
+authentication token from JavaScript.
+
+    💡 HINT 1: When you convert it to a port, the port's name _must_ match
+    the name JavaScript expects in `intro/server/public/index.html`.
+    That name is not `receiveSessionFromJavaScript`, so you will need to
+    rename it to match what JS expects!
+
+    💡 HINT 2: After you rename it, some code in this file will break because
+    it was depending on the old name. Follow the compiler errors to fix them!
+
+-}
+receiveSessionFromJavaScript : (Value -> msg) -> Sub msg
+receiveSessionFromJavaScript toMsg =
+    Sub.none
 
 
 decode : Nav.Key -> Value -> Session

intro/server/elm.json

@@ -3,10 +3,10 @@
     "source-directories": [
         "src"
     ],
-    "elm-version": "0.19.0",
+    "elm-version": "0.19.1",
     "dependencies": {
         "direct": {
-            "NoRedInk/json-decode-pipeline": "1.0.0",
+            "NoRedInk/elm-json-decode-pipeline": "1.0.0",
             "elm/browser": "1.0.0",
             "elm/core": "1.0.0",
             "elm/html": "1.0.0",
@@ -16,7 +16,7 @@
             "elm/url": "1.0.0",
             "elm-explorations/markdown": "1.0.0",
             "lukewestby/elm-http-builder": "6.0.0",
-            "rtfeldman/elm-iso8601": "1.0.1",
+            "rtfeldman/elm-iso8601-date-strings": "1.0.0",
             "rtfeldman/elm-validate": "4.0.0"
         },
         "indirect": {