纯JS中的Angular ng-hide指令

Question

In AngularJS, you could use ng-hide to hide an HTML element. How would you do this using pure JS/jQuery? If you have something like <div id="userNotLoggedIn"></div> , would it be $("#userNotLoggedIn").hide() or $("#userNotLoggedIn").remove() , or something else? The goal is to not allow a site visitor to view a page if they are not logged in as a user.

Answer 1

Well if you want to actually replicate ng-hide, then you would use jQuery.addClass method.

ngHide simply watches for the model value bound to it, and consequently adds/removes ng-hide class. This class simply adds a css rule 'display:none' rendering the element hidden.

However, using it for authentication based roles wouldn't usually be a good idea though. You would be simply making it invisible, but it will still be in the DOM and hence accessible.

Answer 2

Something like

$('#userNotLoggedIn').css('display', 'none');

maybe?

But if you want to be able to apply, and undo it, I recommend putting display: none in it's own class that can be placed and removed at will.

Something like

.myHideClass {
   display: none;
}

$(`#userNotLoggedIn`).addClass('myhideClass');
$(`#userNotLoggedIn`).removeClass('myhideClass');

Now when you do whatever logic you have to see if they're logged, when they are logged in do nothing. If they are not logged in, add myHideClass , once they do log in remove myHideClass

Edit:

One problem though, is I'm pretty sure display: none; is still going to have your elements visible in the DOM if you're in something like a debugger.

Angular has a ng-if attr you can drop on tags and tie to a boolean. Like ng-if="userIsLoggedIn" where userIsLoggedIn is a boolean in your controller that's set to true or false .

In the dom while userIsLoggedIn is true the element and everything in it, is in the dom, but; if userIsLoggedIn === false then in the dom if you inspect it, your div is not visible.

What you'll see in the dom is <!--ng-if="userIsLoggedIn"--> And once the boolean flips to true, then the commented html line will turn into all of your actual html.