Confirm URL using POM Nightwatch - selenium

Question

New to nightwatch and js in general and I'm struggling to figure out how to validate a url using pom pattern. I know this is wrong. Any suggestions are greatly appreciated, including useful links for me to rtfm as I'm struggling to find robust examples of pom nightwatch.
test.js
module.exports = {
"tags": ['sanity'],
'confirm navigation to example.com' : function (client) {
var landingPage = client.page.landing();
landingPage.navigate();
landingPage.confirmOnLandingPage();
client.end();
}
};
page.js
var landingCommands = {
navigate:function(){
url: 'example.com/'
},
confirmOnLandingPage:function(){
this.expect.element('body')
.to.be.present.before(1000)
.url(function(result)
{
this.assert.equal(result.value, 'example.com/', 'On Landing Page.')
});
}
}
Running: confirm navigation to example.com
✖ TypeError:
this.expect.element(...).to.be.present.before(...).url is not a
function
at Page.confirmOnLandingPage (/Users/Home/Development/NWQA/pages/page.js:9:10)
at Object.confirm navigation to example.com (/Users/Home/Development/NWQA/tests/test.js:7:21)
FAILED: 1 errors (18ms)

Answer 1

After running .expect you break the Nightwatch command chain and start Expect.js chain so after you call this.expect.element('body').to.be.present.before(1000) you get Expect.js object and not Nightwatch browser object.
To fix just start a new chain and change this.url call to this.api.url since url() is not available within the page object:
confirmOnLandingPage: function(){
this.expect.element('body').to.be.present.before(1000);
this.api.url(function(result)
{
this.assert.equal(result.value, 'example.com/', 'On Landing Page.')
});
}
Update:
I just noticed you incorrectly declared URL for your page object. navigate is internal function, you only need to provide url property:
var landingCommands = {
url: 'example.com/',
...
};