angularjs - When to use ng-attr?

Question

It seems like using direct attributes and the ng-attr-* directive do the same thing. For example, the following render equivalently:

   <div ng-attr-id="{{ 'object-' + value }}">ID</div>
   <div id="{{ 'object-' + value }}">ID</div>

When should I use ng-attr-* and when should I use the direct HTML attribute?

Answer 1

ng-attr is used for add or not the attribute in context. If the expression {{undefined || null}}, the attribute is not added otherwise if has a value then attribute is added with the value {{ value }}. The most common cases is in interpolation. Related: Conditionally adding data-attribute in Angular directive template