Checking if login works after "Sorry, you are not allowed to edit this post."?

[velara3]

I'm getting an error message when I'm attempting to update a post.

How do I know if login is successful?

I'm able to get a list of posts so the endpoint works.

I'm using the following:

	  var wp = new WPAPI({
			endpoint: apiRoot,
			username: username,
			password: credential,
			auth: true
	  });

	  var test = "posts";

	  // get posts
	  if (test=="posts") {
		log('verify endpoint')
		  wp.posts().then(function( response ) {
				log("response", response)
			}).catch(function(error) {
				log("error", error)
			})
			return;
	  }
	  
	if (test=="update") {
		var postNumber = 28;
		
		var date = new Date()
		var time = date.getTime();
		var update = wp.posts().auth().id( postNumber ).update({
			title: "Time " + time
		})
		.then(function(response){
			console.log("complete");
			console.log(response);
		})
		.catch(function(err){
			log("error:", err);
		});
	}

I've installed and activated this plugin.

{ code: 'rest_cannot_edit',
  message: 'Sorry, you are not allowed to edit this post.',
  data: { status: 401 } 
}

Attempting to create a post returns this:

{ code: 'rest_cannot_create',
  message: 'Sorry, you are not allowed to create posts as this user.',
  data: { status: 401 } 
}

I'm using the download of wpapi.js (7/6/2017) here:

http://wp-api.org/node-wpapi/installation/

FYI I'm not on node. I'm in a client that runs ES6.