JAVASCRIPT

js what is underscore

The Underscore _ Identifier 
A convention has also developed regarding the use of _, 
which is frequently used to preface the name of an object's property
or method that is private. This is a quick and easy way to immediately
identify a private class member, and it is so widely used, that almost
every programmer will recognize it.

underscore javascript

private void Foo() {}
this._foo();

underscore js

Underscore is a JavaScript library that provides a whole mess of useful
functional programming helpers without extending any built-in objects.

underscore js

var numbers = [10, 5, 100, 2, 1000];
_.min(numbers);
=> 2

Underscore.js

var evens = _.filter([1, 2, 3, 4, 5, 6], function(num){ return num % 2 == 0; });
=> [2, 4, 6]