Aff refactor and Suspense experiments

.gitignore

@@ -1,5 +1,6 @@
 /bower_components/
 /node_modules/
+/.spago/
 /.pulp-cache/
 /output/
 /generated-docs/

.prettierrc

@@ -0,0 +1,3 @@
+{
+  "trailingComma": "none"
+}

Makefile

@@ -1,15 +1,27 @@
-all: build examples
+TOPTARGETS := all clean
 
-build: bower_components node_modules
-	npx pulp build
+EXAMPLES := $(wildcard examples/*/.)
 
-examples: bower_components node_modules
-	find examples -maxdepth 2 -type f -iname makefile -execdir make \;
+all: build $(EXAMPLES)
 
-bower_components: node_modules
-	npx bower --allow-root install
+build: output
+
+output: .spago node_modules
+	npx spago build
+
+.spago: node_modules
+	npx spago install
 
 node_modules:
-	npm i --no-save bower pulp purescript
+	npm i --no-save spago purescript bower pulp
+
+clean: $(EXAMPLES)
+	rm -rf node_modules bower_components .spago output
+
+$(EXAMPLES):
+	cd $@ && $(MAKE) $(MAKECMDGOALS)
+
+serve:
+	npx serve
 
-.PHONY: build examples
+.PHONY: build clean $(TOPTARGETS) $(EXAMPLES) serve

README.md

@@ -31,11 +31,12 @@ mkCounter = do
 
 More examples:
 
-- [Counter with an effect](./examples/counter/src/Counter.purs)
-- [Reducer/action-style](./examples/reducer/src/Reducer.purs)
-- [Controlled inputs](./examples/controlled-input/src/ControlledInput.purs)
-- Components: [Parent](./examples/component/src/Container.purs) and [Child](./examples/component/src/ToggleButton.purs)
-- [Refs to DOM nodes](./examples/refs/src/Refs.purs) (and extracting hook logic from a component for reuse)
-- [A Todo App](./examples/todo-app/src/TodoApp.purs) (components, inputs, state)
-- [Context](./examples/context/src/Context.purs) (creating and consuming React context)
-- [Aff helper](./examples/aff/src/AffEx.purs) (async state management)
+- [Counter with an effect](./examples/counter/src/Example.purs)
+- [Reducer/action-style](./examples/reducer/src/Example.purs)
+- [Controlled inputs](./examples/controlled-input/src/Example.purs)
+- Components: [Parent](./examples/component/src/Example.purs) and [Child](./examples/component/src/ToggleButton.purs)
+- [Refs to DOM nodes](./examples/refs/src/Example.purs) (and extracting hook logic from a component for reuse)
+- [A Todo App](./examples/todo-app/src/Example.purs) (components, inputs, state)
+- [Context](./examples/context/src/Example.purs) (creating and consuming React context)
+- [Aff](./examples/aff/src/Example.purs) (rendering async data, using error boundaries)
+- [Suspense](./examples/suspense/src/Example.purs) (experimental, React Suspense demo -- similar to the Aff example, but the loading state is managed by the parent instead of the detail rendering component)

examples/README.md

@@ -0,0 +1,11 @@
+# Examples
+
+## Building an example
+
+In the example folder:
+
+```sh
+make
+```
+
+Then open `html/index.html` in your browser.

examples/aff/Makefile

@@ -1,8 +1,19 @@
-all: node_modules
-	purs compile src/*.purs '../../src/**/*.purs' '../../bower_components/purescript-*/src/**/*.purs'
-	purs bundle -m Main --main Main output/*/*.js > output/bundle.js
-	node_modules/.bin/browserify output/bundle.js -o html/index.js
+parent_sources := $$(npx spago -x ../../spago.dhall sources | sed 's/^/..\/..\//' | tr '\n' ' ')
+
+all: output node_modules
+	npx purs bundle -m Main --main Main output/*/*.js > output/bundle.js
+	npx browserify output/bundle.js -o html/index.js
+
+output: node_modules
+	set -o noglob && \
+	  npx purs compile \
+		  src/**/*.purs \
+		  $(parent_sources)
 
 node_modules:
-	npm install
+	npm i --no-save browserify react react-dom
+
+clean:
+	rm -rf node_modules output
 
+.PHONY: all output clean

examples/aff/src/Example.purs

@@ -0,0 +1,142 @@
+module Example where
+
+import Prelude
+import Data.Foldable (find)
+import Data.Maybe (Maybe(..))
+import Data.Newtype (class Newtype, un)
+import Effect.Aff (Aff, Milliseconds(..), delay, error, message, throwError)
+import React.Basic.DOM as R
+import React.Basic.DOM.Events (capture_)
+import React.Basic.Events (handler_)
+import React.Basic.Hooks (Component, component, fragment, useState, (/\))
+import React.Basic.Hooks as React
+import React.Basic.Hooks.Aff (useAff)
+import React.Basic.Hooks.ErrorBoundary (mkErrorBoundary)
+
+mkExample :: Component Unit
+mkExample = do
+  errorBoundary <- mkErrorBoundary "AffExErrorBoundary"
+  catDetails <- mkCatDetails
+  component "AffEx" \props -> React.do
+    catKey /\ setCatKey <- useState Nothing
+    let
+      reset = setCatKey \_ -> Nothing
+    pure
+      $ R.div_
+          [ R.h2_ [ R.text "Cat chooser" ]
+          , errorBoundary \{ error, dismissError } -> case error of
+              Just e -> renderAppError e (reset *> dismissError)
+              Nothing ->
+                fragment
+                  [ catKeyList catKey setCatKey
+                  , case catKey of
+                      Nothing -> mempty
+                      Just k -> catDetails k
+                  ]
+          ]
+  where
+  -- This component is the main `useAff` demo. It receives a key
+  -- as a prop and renders both the loading state and the final
+  -- result.
+  mkCatDetails :: Component (Key Cat)
+  mkCatDetails = do
+    component "CatDetails" \catKey -> React.do
+      catState <- useAff catKey $ fetch catKey
+      pure
+        $ R.p_
+            [ case map entity catState of
+                Nothing -> R.text "Loading..."
+                Just (Cat { name }) -> R.text $ "A cat named " <> name
+            ]
+
+  renderAppError error resetApp =
+    fragment
+      [ R.p_ [ R.text "Error!" ]
+      , R.p_ [ R.text $ message error ]
+      , R.button
+          { onClick: capture_ do resetApp
+          , children: [ R.text "Reset" ]
+          }
+      ]
+
+  catKeyList selectedCatKey setCatKey =
+    let
+      cats =
+        fakeDb
+          <> [ Entity
+                (Key "error (choose to throw a React render error)")
+                (Cat { name: "" })
+            ]
+
+      catKeyRadioButton k =
+        R.div_
+          [ R.label_
+              [ R.input
+                  { type: "radio"
+                  , name: "cat-key"
+                  , checked: Just k == selectedCatKey
+                  , onChange:
+                      handler_ do
+                        setCatKey \_ -> Just k
+                  }
+              , R.text $ " Cat " <> un Key k
+              ]
+          ]
+    in
+      fragment $ map (catKeyRadioButton <<< key) cats
+
+--
+-- The bits below this point aren't directly relevant to the example,
+-- just a slightly more interesting data model than returing a single
+-- string.
+--
+--
+--
+-- Typed keys are a great way to tie entity-specific behavior
+-- to an ID. We can use this phantom type to write a class
+-- for generic, type-safe data fetching.
+newtype Key entity
+  = Key String
+
+derive instance eqKey :: Eq (Key entity)
+
+derive instance ntKey :: Newtype (Key entity) _
+
+-- An entity wrapper. In a real app this would hold other metadata
+-- such as create and update dates.
+data Entity entity
+  = Entity (Key entity) entity
+
+key :: forall entity. Entity entity -> Key entity
+key (Entity k _) = k
+
+entity :: forall entity. Entity entity -> entity
+entity (Entity _ e) = e
+
+class Fetch entity where
+  fetch :: Key entity -> Aff (Entity entity)
+
+-- An example entity
+newtype Cat
+  = Cat { name :: String }
+
+fakeDb :: Array (Entity Cat)
+fakeDb =
+  [ Entity (Key "abc") (Cat { name: "Herb" })
+  , Entity (Key "def") (Cat { name: "Maxi" })
+  , Entity (Key "ghi") (Cat { name: "Chloe" })
+  ]
+
+instance fetchCat :: Fetch Cat where
+  fetch k = do
+    delay $ Milliseconds 300.0
+    -- pretend this happens on the server
+    case fakeDb # find (key >>> (_ == k)) of
+      Nothing ->
+        -- This should never happen in a normal application path
+        -- if only the server can generate keys :)
+        throwError
+          $ error
+          $ "DB error: Cat not found for key "
+          <> un Key k
+      Just e -> pure e