I learning AngularJS, and I have some misunderstanding on this example:
(function () {
"use strict";
angular.module("productManagement").controller("ProductListCtrl", ProductListCtrl);
function ProductListCtrl() {
    var vm = this;
    vm.products = [
    {
        "productId": 1,
        "productName": "Leaf Rake",
        "productCode": "GDN-0011",
        "releaseDate": "March 19, 2009",
        "description": "Leaf rake with 48-inch wooden handle.",
        "price": 19.95
    },
    {
        "productId": 2,
        "productName": "Garden Cart",
        "productCode": "GDN-0023",
        "releaseDate": "March 18, 2010",
        "description": "15 gallon capacity rolling garden cart",
        "price": 32.99
    },
     {
         "productId": 5,
         "productName": "Hammer",
         "productCode": "TBX-0048",
         "releaseDate": "May 21, 2013",
         "description": "Curved claw steel hammer",
         "price": 8.99
     },
     {
         "productId": 8,
         "productName": "Saw",
         "productCode": "TBX-0022",
         "releaseDate": "May 15, 2009",
         "description": "15-inch steel blade hand saw",
         "price": 11.55
     },
     {
         "productId": 10,
         "productName": "Video Game Controller",
         "productCode": "GMG-0042",
         "releaseDate": "October 15, 2002",
         "description": "Standard two-button video game controller",
         "price": 35.95
     }
    ];
  }
 }());
What is meaning of this row:
var vm = this;
What is the meaning of this keyword in current context?
 
    