Understanding the Power of ::ng-Deep in Angular 4

Seeking a method to override CSS properties in child components from parent components? Angular 4 introduces the concept of ::ng-deep, an alternative to the deprecated /deep/ selector. This "shadow-piercing" combinator allows styles to traverse into encapsulated child components.

Syntax and Usage

To utilize ::ng-deep, simply employ the syntax ::ng-deep selector within your CSS rules. For instance:

.overview {
    ::ng-deep {
        p {
            &:last-child {
                margin-bottom: 0;
            }
        }
    }
}

In this example, the style specified within ::ng-deep will be applied to all matching elements in all child components within the parent component, including deeply nested ones.

Compatibility with IE11

It's worth noting that ::ng-deep is not officially supported in Internet Explorer 11 (IE11). While certain IE11 versions may partially support it, it's recommended to use alternative methods when targeting IE11 browsers.

Benefits and Considerations

Using ::ng-deep can simplify styling complex component structures by allowing access to deeply nested elements. However, it's important to use it judiciously as it bypasses encapsulation, potentially leading to style conflicts or unexpected behavior. Use ::ng-deep whenever necessary, but consider exploring safer alternatives whenever possible.