How can I wait for a condition?

Protractor 1.7.0 has also introduced a new feature: Expected Conditions.

There are several predefined conditions to explicitly wait for. In case you want to wait for an element to become present:

var EC = protractor.ExpectedConditions;

var e = element(by.id('xyz'));
browser.wait(EC.presenceOf(e), 10000);

expect(e.isPresent()).toBeTruthy();

See also:

• Expected conditions in protractor

I finally find out...

   var waitLoading = by.css('#loading.loader-state-hidden');

   browser.wait(function() {
       return ptor.isElementPresent(waitLoading);
   }, 8000);

   expect(ptor.isElementPresent(waitLoading)).toBeTruthy();

   var openContact = by.xpath("//a[@href='#/contacts']");
   element(openContact).click();

With this protractor could wait for that element until it loading page disappears. Thanks for those who tried to help XD.