Underscore.js Arrays: Flatten

HTML

<script src="http://documentcloud.github.com/underscore/underscore-min.js"></script>
<a target="parent" href="http://underscorejs.org/#flatten">Learn More</a>

JavaScript

var testFullFlatten = _.flatten([1, [2], [3, [[4]]]]);
var testShallowFlatten = _.flatten([1, [2], [3, [[4]]]], true);


//Full Flatten
console.log(testFullFlatten);
//[1, 2, 3, 4] 

//Only flattens one level
console.log(testShallowFlatten);
//[1, 2, 3, Array[1]]

var data = [[1, 2],[3, 4, 5], [6, 7, 8, 9]]; 
console.log(_.flatten(data));