docs(mvc.Collection): add docs and testing for updated collection met… (#2474)

Author: jamesgeorgewilliams

packages/joint-core/docs/src/joint/api/mvc/Collection/prototype/each.html

@@ -0,0 +1,19 @@
+<pre class="docs-method-signature"><code>collection.each(fn, [context])</code></pre>
+
+<p>
+    Iterate over models of a collection, and invoke <code>fn</code> for each model. <code>fn</code> is invoked with 3 arguments:
+    <i>(model, index, array)</i>.
+</p>
+
+<pre><code>const a = new mvc.Model({ id: 1, label: 'a' });
+const b = new mvc.Model({ id: 2, label: 'b' });
+const c = new mvc.Model({ id: 3, label: 'c' });
+const col = new mvc.Collection([a, b, c]);
+
+col.each((model, i) => model.set({ customData: i }));
+
+col.each((model) => console.log(model.get('customData')));
+// 0
+// 1
+// 2
+</code></pre>

packages/joint-core/docs/src/joint/api/mvc/Collection/prototype/filter.html

@@ -0,0 +1,15 @@
+<pre class="docs-method-signature"><code>collection.filter(fn, [context])</code></pre>
+
+<p>
+    Iterate over models of a collection, returning an array of all models <code>fn</code> returns truthy for. <code>fn</code> is invoked with three
+    arguments: <i>(model, index, array)</i>.
+</p>
+
+<pre><code>const a = new mvc.Model({ id: 3, label: 'a' });
+const b = new mvc.Model({ id: 2, label: 'b' });
+const c = new mvc.Model({ id: 1, label: 'c' });
+const d = new mvc.Model({ id: 0, label: 'd' });
+const col = new mvc.Collection([a, b, c, d]);
+
+console.log(col.filter((model) => model.get('id') === 0).length); // 1
+</code></pre>

packages/joint-core/docs/src/joint/api/mvc/Collection/prototype/first.html

@@ -0,0 +1,5 @@
+<pre class="docs-method-signature"><code>collection.first()</code></pre>
+
+<p>
+    Return the first model of a collection.
+</p>

packages/joint-core/docs/src/joint/api/mvc/Collection/prototype/includes.html

@@ -0,0 +1,15 @@
+<pre class="docs-method-signature"><code>collection.includes(value)</code></pre>
+
+<p>
+    Return <code>true</code> if model is found in a collection.
+</p>
+
+<pre><code>const a = new mvc.Model({ id: 3, label: 'a' });
+const b = new mvc.Model({ id: 2, label: 'b' });
+const c = new mvc.Model({ id: 1, label: 'c' });
+const d = new mvc.Model({ id: 0, label: 'd' });
+const col = new mvc.Collection([a, b, c]);
+
+console.log(col.includes(a)); // true
+console.log(col.includes(d)); // false
+</code></pre>

packages/joint-core/docs/src/joint/api/mvc/Collection/prototype/isEmpty.html

@@ -0,0 +1,14 @@
+<pre class="docs-method-signature"><code>collection.isEmpty()</code></pre>
+
+<p>
+    Return <code>true</code> if a collection is empty.
+</p>
+
+<pre><code>const col = new mvc.Collection([]);
+
+console.log(col.isEmpty()); // true
+
+col.set([new mvc.Model({ id: 1, label: 'a' })]);
+
+console.log(col.isEmpty()); // false
+</code></pre>

packages/joint-core/docs/src/joint/api/mvc/Collection/prototype/last.html

@@ -0,0 +1,5 @@
+<pre class="docs-method-signature"><code>collection.last()</code></pre>
+
+<p>
+    Return the last model of a collection.
+</p>

packages/joint-core/docs/src/joint/api/mvc/Collection/prototype/map.html

@@ -0,0 +1,15 @@
+<pre class="docs-method-signature"><code>collection.map(fn, [context])</code></pre>
+
+<p>
+    Create an array of values by running each model in the collection through <code>fn</code>. <code>fn</code> is invoked with three arguments:
+    <i>(model, index, array)</i>.
+</p>
+
+<pre><code>const a = new mvc.Model({ id: 3, label: 'a' });
+const b = new mvc.Model({ id: 2, label: 'b' });
+const c = new mvc.Model({ id: 1, label: 'c' });
+const d = new mvc.Model({ id: 0, label: 'd' });
+const col = new mvc.Collection([a, b, c, d]);
+
+console.log(col.map((model) => model.get('label')).join(' ')); // 'a b c d'
+</code></pre>

packages/joint-core/docs/src/joint/api/mvc/Collection/prototype/pluck.html

@@ -0,0 +1,12 @@
+<pre class="docs-method-signature"><code>collection.reduce(fn, [initialValue])</code></pre>
+
+<p>
+    Reduce a collection to a value which is the accumulated result of running each model in the collection through <code>fn</code>, where each
+    successive invocation is supplied the return value of the previous. If <code>initialValue</code> is not given, the first model in the collection
+    is used as the initial value. <code>fn</code> is invoked with four arguments: <i>(accumulator, currentValue, currentIndex, array)</i>.
+</p>
+
+<pre><code>const collection = new mvc.Collection([new mvc.Model({ id: 1, label: 'a' })]);
+
+console.log(collection.reduce((acc, model) => acc.get('id') + model.id )); // 2
+</code></pre>

packages/joint-core/docs/src/joint/api/mvc/Collection/prototype/reduce.html

@@ -354,8 +354,8 @@ assign(Collection.prototype, Events, {
     },
 
     // Runs "reducer" fn over all elements in the collection, in ascending-index order, and accumulates them into a single value
-    reduce: function(fn, initAcc, context) {
-        return this.models.reduce(fn, initAcc, context);
+    reduce: function(fn, initAcc = this.first()) {
+        return this.models.reduce(fn, initAcc);
     },
 
     // Private method to reset all internal state. Called when the collection