This is an example of how to post an item to a SharePoint 2013 list. You must have the list itemType and list contextinfo tokens available prior to adding items to SharePoint via REST API.

addListItemByTitle.coffee

user = "domain\\username"
pass = "password"
url  = "http://sharepoint/siteCollection"
list = "listName" 

# These two variables need to be obtained from the sharepoint server
itemType = "SP.Data.SomethingListItem"
context  = "some really long hex string value"
 
# Define the request fn
request = require 'request'

addListItemByTitle: (title, item, context, cb)->
  processRequest = (err, res, body)->
    cb(err, JSON.parse(body).d)

  config =
    headers :
      "Accept": "application/json;odata=verbose"
      "X-RequestDigest": context
      "content-type": "application/json;odata=verbose"
    url     : "#{url}/_api/web/lists/getbytitle('#{title}')/items"
    body: JSON.stringify(item)

  request.post(config, processRequest).auth(user, pass, true)


# Run the request
item =
  __metadata:
    type: itemType
  Title: "NodeGeneratedTest" + Math.random()

addListItemByTitle list, item, context, (err, res)->
  console.log err || res