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POHow do I sort a coffeescript Map object by property value?
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copied!<p>I have a list of <code>articles</code> each of which has a simple string array of <code>Tags</code>. I count the tag frequency like this:</p> <p><strong>Count The Tag Frquency</strong></p> <pre><code>getTags = (articles) -> tags= {} for article in articles for tag in article.Tags tags[tag] = (tags[tag] or 0) + 1 tags </code></pre> <p><strong>Example Result</strong></p> <p>The <code>tags</code> map produced is an object with property names set to the <code>Tag</code> name and property values set to the frequency count, like so:</p> <p><img src="https://i.stack.imgur.com/oXnGb.png" alt="enter image description here"></p> <p><strong>Question</strong></p> <p>I would like to order this list by the property value (the frequency count), how can I achieve this? </p> <p>Note: <em>I am happy to change the counting method if required</em></p> <p><strong>Edit 1</strong></p> <p>Thanks to @LeonidBeschastny I now have working code:</p> <pre><code>getTags = (articles) -> tags = {} for article in articles for tag in article.Tags tags[tag] = (tags[tag] or 0) + 1 tags = do (tags) -> keys = Object.keys(tags).sort (a, b) -> tags[b] - tags[a] {name, count: tags[name]} for name in keys tags </code></pre> <p>You can see that I am having to project the unsorted <code>tags</code> map object into a new array of sorted <code>{name:value}</code> objects. </p> <p>This feels like it is too much work and I think maybe the original unsorted object was a mistake. Is there a way to get to the sorted array without going through this intermediate step?</p> <p><strong>Edit 2</strong></p> <p>Thanks to @hpaulj for doing some time tests and discovering that the code above is actually reasonably efficient compared to other potential solutions, such as a running sorted heap.</p> <p>I have now put this code into production and it is working well.</p>

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