SP.Web.EnsureUser(user) does not seem to work. (JavaScript Client OM)

Question

Supposedly, SP.Web.ensureUser(user) works according to this MSDN link but I cannot seem to get it to work in my JS code.

While debugging, I can see that SP.Web exists and the user variable is populated with the user that I expect. However I get the following exception:

Object function (b,a){ULSdih:;SP.Web.initializeBase(this,[b,a])} has no method 'ensureUser' 

Answer 1

You will have to call the ensureUser method against a valid web object. The following code should work:

var context = SP.ClientContext.get_current();
var theUser = context.get_web().ensureUser("DEV\testowner");
context.load(theUser);

context.executeQueryAsync(function(){

 alert(theUser.get_title());

},
function(sender, args){

  alert(args.get_message());

});