Basic Example for underscore use in JavaScript

_example.js

// Option A
var threes = _.map([1, 2, 3], function(num){ return num * 3; });
// threes => [3, 6, 9]

var odds = _.filter(threes, function(num) { return num % 2 != 0; });
// oddss => [3, 9]

// Option B
var odds = _.filter(_.map([1, 2, 3], function(num){ return num * 3; }), function(num) { return num % 2 != 0; });

// Option C
var odds = _.chain([1, 2, 3])
  .map(function(num){ return num * 3; })
  .filter(function(num) { return num % 2 != 0; })
  .value()