Underscore.js it is JavaScript library and contains more than 60 methods.

1) Underscore.js simplifies the work with collections, arrays:
• sort items sortBy
• search for items find
• retooling elements shuffle
• intersection of arrays intersection
• and other features ...

2) Underscore.js simplifies the check for equality of objects:
• compares objects by values isEqual
• is it a function isFunction
• and other features ...

3) Underscore.js contains other useful methods