When to favor ng-if vs. ng-show/ng-hide?

Question

I understand that ng-show and ng-hide affect the class set on an element and that ng-if controls whether an element is rendered as par

Answer 1

The answer is not simple:

It depends on the target machines (mobile vs desktop), it depends on the nature of your data, the browser, the OS, the hardware it runs on... you will need to benchmark if you really want to know.

It is mostly a memory vs computation problem ... as with most performance issues the difference can become significant with repeated elements (n) like lists, especially when nested (n x n, or worse) and also what kind of computations you run inside these elements:

• ng-show: If those optional elements are often present (dense), like say 90% of the time, it may be faster to have them ready and only show/hide them, especially if their content is cheap (just plain text, nothing to compute or load). This consumes memory as it fills the DOM with hidden elements, but just show/hide something which already exists is likely to be a cheap operation for the browser.

• ng-if: If on the contrary elements are likely not to be shown (sparse) just build them and destroy them in real time, especially if their content is expensive to get (computations/sorted/filtered, images, generated images). This is ideal for rare or 'on-demand' elements, it saves memory in terms of not filling the DOM but can cost a lot of computation (creating/destroying elements) and bandwidth (getting remote content). It also depends on how much you compute in the view (filtering/sorting) vs what you already have in the model (pre-sorted/pre-filtered data).