Fix assignment error; and flesh out exmaple

Author: Victor Alvarez

features.txt

@@ -1246,12 +1246,17 @@ Memory-leak-free Object-key’d side-by-side data-structures.
 6|     get data    ()     { return |attachedData.get|(this); }
 6| }
 6|
-6| new foo = new Node("foo");
+6| let foo = new Node("foo");
 6| JSON.stringify(foo) === |'{"id":"foo"}'|;
 6| foo.mark();
 6| foo.data = "bar";
 6| foo.data === "bar";
 6| JSON.stringify(foo) === |'{"id":"foo"}'|;
+6| isMarked.has(foo) === true
+6| attachedData.has(foo) === true
+6| foo = null // remove only reference to foo
+6| attachedData.has(foo) === false 
+6| isMarked.has(foo) === false
 
 5| // no equivalent in ES5
 

index.html

@@ -1707,12 +1707,17 @@
     get data    <span class="punctuation">(</span><span class="punctuation">)</span>     <span class="punctuation">{</span> <span class="keyword">return</span> <span class="mark">attachedData<span class="punctuation">.</span>get</span><span class="punctuation">(</span><span class="keyword">this</span><span class="punctuation">)</span><span class="semi">;</span> <span class="punctuation">}</span>
 <span class="punctuation">}</span>
 
-<span class="keyword">new</span> foo<span class="punctuation"> = </span><span class="keyword">new</span> Node<span class="punctuation">(</span><span class="literal">"foo"</span><span class="punctuation">)</span><span class="semi">;</span>
+<span class="keyword">let</span> foo<span class="punctuation"> = </span><span class="keyword">new</span> Node<span class="punctuation">(</span><span class="literal">"foo"</span><span class="punctuation">)</span><span class="semi">;</span>
 JSON<span class="punctuation">.</span>stringify<span class="punctuation">(</span>foo<span class="punctuation">)</span> <span class="punctuation">===</span> <span class="mark"><span class="literal">'<span class="punctuation">{</span>"id":"foo"<span class="punctuation">}</span>'</span></span><span class="semi">;</span>
 foo<span class="punctuation">.</span>mark<span class="punctuation">(</span><span class="punctuation">)</span><span class="semi">;</span>
 foo<span class="punctuation">.</span>data<span class="punctuation"> = </span><span class="literal">"bar"</span><span class="semi">;</span>
 foo<span class="punctuation">.</span>data <span class="punctuation">===</span> <span class="literal">"bar"</span><span class="semi">;</span>
 JSON<span class="punctuation">.</span>stringify<span class="punctuation">(</span>foo<span class="punctuation">)</span> <span class="punctuation">===</span> <span class="mark"><span class="literal">'<span class="punctuation">{</span>"id":"foo"<span class="punctuation">}</span>'</span></span><span class="semi">;</span>
+isMarked<span class="punctuation">.</span>has<span class="punctuation">(</span>foo<span class="punctuation">)</span> <span class="punctuation">===</span> true
+attachedData<span class="punctuation">.</span>has<span class="punctuation">(</span>foo<span class="punctuation">)</span> <span class="punctuation">===</span> true
+foo<span class="punctuation"> = </span>null<span class="comment"> // remove only reference to foo</span>
+attachedData<span class="punctuation">.</span>has<span class="punctuation">(</span>foo<span class="punctuation">)</span> <span class="punctuation">===</span> false 
+isMarked<span class="punctuation">.</span>has<span class="punctuation">(</span>foo<span class="punctuation">)</span> <span class="punctuation">===</span> false
 </div>
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