Should I use a single directive with ng-if statements in AngularJS, or opt for two separate directives?

Question about optimizing performance in Angular JS.

I am using ng-repeat to display a list of search results. Each search item is extracted using a directive/template.

Should I wrap two directives with ng-if statements or use one directive with multiple ng-if statements, and utilize expressions or statements?

For example, using ng-if statements to wrap two directives:

<div ng-repeat>
    <directive-1 ng-if="this"></directive-1>
    <directive-2 ng-if="that"></directive-2>
</div>

OR

<div ng-repeat>
   <directive-1></directive-1>
</div>

and inside directive-1 you have...

<img src="1" ng-if="this">
<img src="2" ng-if="that">
<span>{{title || title2}}</span>
etc...

Answer №1

Explaining the role of ng-if: A directive (1) that utilizes an isolated scope (2) to either remove or append DOM elements (3).

What are the implications of this?

  1. Ng-if requires initialization time, albeit minimal.

  2. Ng-if establishes a new isolated scope, with minimal impact.

  3. Ng-if interacts with the DOM, which can potentially be a resource-intensive task.

Hence, the primary performance concern lies in DOM manipulation. The most effective strategy to enhance ng-if performance is by minimizing DOM manipulations.

Moreover, it is advisable to exercise caution when combining ng-if with ng-repeat. While feasible, it should be done with care.

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