Understanding the Purpose of the 'ng-container' Tag in Angular

In Angular, the 'ng-container' tag serves a very specific role and that is "to conditionally group elements without adding extra DOM nodes". This underlines an important philosophy behind coding efficiently in Angular or, indeed, any other coding language.

An Introduction to 'ng-container'

The 'ng-container' tag is a grouping element that doesn't interfere with styles or layout because Angular doesn't put it in the DOM. This means it's not translated into an actual DOM element, but serves as a cure for cases when the structural directives, such as '*ngIf', '*ngFor', or '*ngSwitch', need to be placed on multiple elements.

Practical Application of 'ng-container'

Let's think of an example: if you want to use an *ngIf directive to conditionally hide or show a couple of consecutive elements, without messing up with your html layout, you could wrap them all in a single 'ng-container'.

<ng-container *ngIf="showElements">
  <div>Your content here</div>
  <div>And maybe some more...</div>
</ng-container>

In this way, you would not have to put the *ngIf on each of the 'div' individually, also avoiding to add more unwanted 'div' in the DOM that could potentially mess up the html layout and CSS style.

Best Practices for Using 'ng-container'

'ng-container' is ideal for conditions involving multiple sibling elements and you should avoid its unnecessary use when possible. Remember, 'ng-container' is not a catch-all solution but a tool to use in certain circumstances.

Moreover, 'ng-container' should not be used as a makeshift to avoid structuring your code properly. It aids in grouping elements under conditions, but it's best to also consider how components and services can be built to be reusable or how templates can be written efficiently.

In conclusion, the 'ng-container' tool in Angular helps with conditional grouping of elements, ensuring your code is efficient and well-structured. Its smart use contributes towards better readability and maintainability of your code.