Underscore is a library that nicely rounds out JavaScript’s rather limited standard library. Thanks to the Node Package Manager, it’s very simple to install on Node.js:
$ npm install underscoreThen you can use it in code as follows:
var _ = require("underscore");If you want to play with Underscore interactively in the Node.js REPL, you can’t give it the name _, because that is used by the REPL, to hold the previous input:
> 3 + 4 7 > _ 7Solution: choose another name.
> var u = require("underscore"); > u.uniq([5, 3, 5, 5, 3, 1]) [ 5, 3, 1 ]