AngularJS - ngIf Vs. ngShow

2017-05-16 JavaScript

At a first look, ng-if and ng-show seems logically very similar except one major difference.

ngShow (or ng-show)

ng-show will be generating the whole element at a time of rendering a web page. However, it will be hidden the element using angular class in case of false condition.

In simple words, the element, where the ng-show has been declared over that will be available on a web page (including its child elements) and can be seen by removing angular specific class that hides them.

ngIf (or ng-if)

As mentioned above, ng-if works in similar fashion but with little difference. ng-if doesn’t generate the element on which the condition ng-if has applied. That means, it will be removed the element completely from the DOM tree structure, if condition is not matched.

Why using ng-if is better than ng-show?

If you have used ng-show in your code, where you have <img src='path-to-image' /> defined as a child element and that is unfortunately having wrong path, you might get 404 error, even though the logical condition is false. The only reason is that the browser would scan the whole page available as DOM and so the elements inside ng-show DIV/P.

On the other hand, ng-if will be removed the DOM from the tree structure and hence we could fix a bug of getting 404 error. 404 error is a status error, if resource is NOT FOUND.

Below, I have put a JSFIDDLE example to get a better idea:

Have a great coding and put your comments below for any discussion/confusion.

Thanks :)

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