Object definition SyntaxError
<p>Why does the second line of code produce an error but not the third?</p>

<pre><code>{ foo: 'bar' } // =&gt; 'bar'

{ "foo": 'bar' } // =&gt; SyntaxError: Invalid label

({ "foo": 'bar' }) // =&gt; { foo: 'bar' }.
</code></pre>
