add *failing* test for DELETE an item #59

Author: nelsonic

Diff for: examples/counter-basic/index.html

@@ -95,22 +95,22 @@
 <script src="../counter-basic-test/test.js"></script> <!-- load test.js last -->
 
 <div onclick="doubleclick(this, function(){alert('single')}, function(){alert('double')})">click me</div>
-    <script>
-        function doubleclick(el, onsingle, ondouble) {
-            if (el.getAttribute("data-dblclick") == null) {
-                el.setAttribute("data-dblclick", 1);
-                setTimeout(function () {
-                    if (el.getAttribute("data-dblclick") == 1) {
-                        onsingle();
-                    }
-                    el.removeAttribute("data-dblclick");
-                }, 300);
-            } else {
-                el.removeAttribute("data-dblclick");
-                ondouble();
-            }
+<script>
+  function doubleclick(el, onsingle, ondouble) {
+    if (el.getAttribute("data-dblclick") == null) {
+      el.setAttribute("data-dblclick", 1);
+      setTimeout(function () {
+        if (el.getAttribute("data-dblclick") == 1) {
+          onsingle();
         }
-    </script>
+        el.removeAttribute("data-dblclick");
+      }, 300);
+    } else {
+      el.removeAttribute("data-dblclick");
+      ondouble();
+    }
+  }
+</script>
 
 </body>
 </html>

Diff for: examples/todo-list/elmish.js

@@ -31,7 +31,7 @@ function mount (model, update, view, root_element_id, subscriptions) {
     root.appendChild(view(mod, sig)) // render view based on model & signal
   }
 
-  function signal(action, data) { // signal function takes action
+  function signal(action, data, model) { // signal function takes action
     return function callback() { // and returns callback
       model = JSON.parse(localStorage.getItem(store_name)) //|| model;
       var updatedModel = update(action, model, data); // update model for the action

Diff for: examples/todo-list/todo-app.js

@@ -13,11 +13,13 @@ var initial_model = {
 /**
  * `update` transforms the `model` based on the `action`.
  * @param {String} action - the desired action to perform on the model.
- * @param {Object} model - the App's (current) model (or "state").
  * @param {String} data - the data we want to "apply" to the item.
+ * @param {Object} model - the App's (current) model (or "state").
  * @return {Object} updated_model - the transformed model.
  */
 function update(action, model, data) {
+  console.log(arguments)
+  console.log(' - - - - - - - - - - - ');
   var new_model = JSON.parse(JSON.stringify(model)) // "clone" the model
   switch(action) {                   // and an action (String) runs a switch
     case 'ADD':
@@ -51,6 +53,9 @@ function update(action, model, data) {
         item.done = new_model.all_done;
       });
       break;
+    // case 'DELETE':
+    //   console.log('DELETE', data)
+    //   break;
     default: // if action unrecognised or undefined,
       return model; // return model unmodified
   }   // see: https://softwareengineering.stackexchange.com/a/201786/211301
@@ -66,12 +71,14 @@ function update(action, model, data) {
  * + `<button class="destroy">` lets people "delete" a todo item.
  * see: https://github.com/dwyl/learn-elm-architecture-in-javascript/issues/52
  * @param  {Object} item the todo item object
+ * @param {Object} model - the App's (current) model (or "state").
+ * @param {Function} singal - the Elm Architicture "dispacher" which will run
  * @return {Object} <li> DOM Tree which is nested in the <ul>.
  * @example
  * // returns <li> DOM element with <div>, <input>. <label> & <button> nested
  * var DOM = render_item({id: 1, title: "Build Todo List App", done: false});
  */
-function render_item (item, signal) {
+function render_item (item, model, signal) {
   return (
     li([
       "data-id=" + item.id,
@@ -87,7 +94,7 @@ function render_item (item, signal) {
           ],
           []), // <input> does not have any nested elements
         label([], [text(item.title)]),
-        button(["class=destroy"])
+        button(["class=destroy", ]) // signal('DELETE', 'blah!', model)])
       ]) // </div>
     ]) // </li>
   )
@@ -97,6 +104,7 @@ function render_item (item, signal) {
  * `render_main` renders the `<section class="main">` of the Todo List App
  * which contains all the "main" controls and the `<ul>` with the todo items.
  * @param {Object} model - the App's (current) model (or "state").
+ * @param {Function} singal - the Elm Architicture "dispacher" which will run
  * @return {Object} <section> DOM Tree which containing the todo list <ul>, etc.
  */
 function render_main (model, signal) {
@@ -114,8 +122,9 @@ function render_main (model, signal) {
       label(["for=toggle-all"], [ text("Mark all as complete") ]),
       ul(["class=todo-list"],
         (model.todos && model.todos.length > 0) ?
-        model.todos.map(function (item) { return render_item(item, signal) })
-        : null
+        model.todos.map(function (item) {
+          return render_item(item, model, signal)
+        }) : null
       ) // </ul>
     ]) // </section>
   )
@@ -126,6 +135,7 @@ function render_main (model, signal) {
  * which contains count of items to (still) to be done and a `<ul>` "menu"
  * with links to filter which todo items appear in the list view.
  * @param {Object} model - the App's (current) model (or "state").
+ * @param {Function} singal - the Elm Architicture "dispacher" which will run
  * @return {Object} <section> DOM Tree which containing the <footer> element.
  * @example
  * // returns <footer> DOM element with other DOM elements nested:
@@ -183,6 +193,7 @@ function render_footer (model, signal) {
  * which contains count of items to (still) to be done and a `<ul>` "menu"
  * with links to filter which todo items appear in the list view.
  * @param {Object} model - the App's (current) model (or "state").
+ * @param {Function} singal - the Elm Architicture "dispacher" which will run
  * @return {Object} <section> DOM Tree which containing all other DOM elements.
  * @example
  * // returns <section class="todo-app"> DOM element with other DOM els nested:

Diff for: test/todo-app.test.js

@@ -67,7 +67,9 @@ test('render_item HTML for a single Todo Item', function (t) {
     hash: '#/' // the "route" to display
   };
   // render the ONE todo list item:
-  document.getElementById(id).appendChild(app.render_item(model.todos[0]))
+  document.getElementById(id).appendChild(
+    app.render_item(model.todos[0]),
+  )
 
   const done = document.querySelectorAll('.completed')[0].textContent;
   t.equal(done, 'Learn Elm Architecture', 'Done: Learn "TEA"');
@@ -307,7 +309,7 @@ test('3. Mark all as completed ("TOGGLE_ALL")', function (t) {
   t.end();
 });
 
-test('4. Item, should allow me to mark items as complete', function (t) {
+test('4. DELETE an item', function (t) {
   elmish.empty(document.getElementById(id));
   localStorage.removeItem('elmish_' + id);
   const model = {
@@ -337,7 +339,7 @@ test('4. Item, should allow me to mark items as complete', function (t) {
   t.end();
 });
 
-test.skip('4.1 Item, should allow me to edit an item ("EDIT")' , function (t) {
+test.only('4.1 DELETE item by clicking <button class="destroy">', function (t) {
   elmish.empty(document.getElementById(id));
   localStorage.removeItem('elmish_' + id);
   const model = {
@@ -348,10 +350,16 @@ test.skip('4.1 Item, should allow me to edit an item ("EDIT")' , function (t) {
   };
   // render the view and append it to the DOM inside the `test-app` node:
   elmish.mount(model, app.update, app.view, id, app.subscriptions);
+  // const todo_count = ;
+  t.equal(document.querySelectorAll('.destroy').length, 1, "one destroy button")
+
   const item = document.getElementById('0')
   t.equal(item.textContent, model.todos[0].title, 'Item contained in model.');
-  // confirm that the todo item is NOT done (done=false):
-
-
+  // DELETE the item by clicking on the <button class="destroy">:
+  const button = item.querySelectorAll('button.destroy')[0];
+  button.click()
+  // confirm that there is no loger a <button class="destroy">
+  t.equal(document.querySelectorAll('button.destroy').length, 0,
+    'there is no loger a <button class="destroy"> as the only item was DELETEd')
   t.end();
 });

Diff for: todo-list.md

@@ -1781,13 +1781,100 @@ function render_item (item, signal) {
 ```
 
 
-
 #### 4.1 `DELETE` an Item
 
 ```
 should show the remove button on hover
 ```
 
+##### Acceptance Criteria
+
++ [ ] should show the `<button class="destroy">`
+on hover (over the item) ... thankfully the TodoMVC CSS
+handles this for us, we just need our `view`
+to render the `<button>`
++ [ ] Clicking/tapping the `<button class="destroy">`
+sends the `signal('DELETE', todo.id, model)`
++ [ ] The `DELETE` update case receives the `todo.id`
+and removes it from the `model.todos` Array.
+
+In order to `DELETE` an item from the `model.todos` Array,
+we need to "_supply_" the `model` when invoking the `signal`
+function. This means we need to _extend_ the `signal` function's
+parameters to include the `model` as an _optional_ argument.
+
+In the `elmish.js` file, locate the `mount` function
+and add a `model` parameter to the `signal` function definition.
+Thus it should change from:
+```js
+function signal(action, data) { // signal function takes action
+  return function callback() { // and returns callback
+    model = JSON.parse(localStorage.getItem(store_name)) //|| model;
+    var updatedModel = update(action, model, data); // update model for the action
+    render(updatedModel, signal, ROOT);
+  };
+};
+```
+
+To:
+```js
+function signal(action, data, model) { // signal function takes action
+  return function callback() { // and returns callback
+    model = JSON.parse(localStorage.getItem(store_name)) //|| model;
+    var updatedModel = update(action, model, data); // update model for the action
+    render(updatedModel, signal, ROOT);
+  };
+};
+```
+
+Thankfully, we have a "bank" (or "suite") of tests that cover
+all of our existing functionality,
+so when we make a change like this
+we can _confirm_ that all _existing_ functionality
+still works as expected.
+
+Run the tests: `npm test` and ensure they all still pass
+after making the change to the `signal` function. (_they should!_)
+
+![tests-still-passing](https://user-images.githubusercontent.com/194400/44953303-a109ce00-ae93-11e8-8f0c-c271832df3a5.png)
+
+
+##### `DELETE` Item _Test_
+
+Append following test code to your `test/todo-app.test.js` file:
+
+```js
+test.only('4.1 DELETE item by clicking <button class="destroy">', function (t) {
+  elmish.empty(document.getElementById(id));
+  localStorage.removeItem('elmish_' + id);
+  const model = {
+    todos: [
+      { id: 0, title: "Make something people want.", done: false }
+    ],
+    hash: '#/' // the "route" to display
+  };
+  // render the view and append it to the DOM inside the `test-app` node:
+  elmish.mount(model, app.update, app.view, id, app.subscriptions);
+  // const todo_count = ;
+  t.equal(document.querySelectorAll('.destroy').length, 1, "one destroy button")
+
+  const item = document.getElementById('0')
+  t.equal(item.textContent, model.todos[0].title, 'Item contained in model.');
+  // DELETE the item by clicking on the <button class="destroy">:
+  const button = item.querySelectorAll('button.destroy')[0];
+  button.click()
+  // confirm that there is no loger a <button class="destroy">
+  t.equal(document.querySelectorAll('button.destroy').length, 0,
+    'there is no loger a <button class="destroy"> as the only item was DELETEd')
+  t.end();
+});
+```
+
+If you run the tests `node test/todo-app.test.js` 
+you should now see:
+![delete-test-one-assertion-failing](https://user-images.githubusercontent.com/194400/44953479-21313300-ae96-11e8-971a-51757702bacc.png)
+
+
 
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