Overview for badge
Badges are small status descriptors for UI elements. A badge consists of a small circle, typically containing a number or other short set of characters, that appears in proximity to another object.
Badges must always be applied to block-level elements.
By default, the badge will be placed above after. The direction can be changed by defining
the attribute matBadgePosition follow by above|below and before|after.
<button mat-raised-button color="primary"
matBadge="8" matBadgePosition="before" matBadgeColor="accent">
Action
</button> The overlap of the badge in relation to its inner contents can also be defined
using the matBadgeOverlap tag. Typically, you want the badge to overlap an icon and not
a text phrase. By default it will overlap.
<div matBadge="4" matBadgeOverlap="false" class="demo-section">Text with a badge</div>
The badge has 3 sizes: small, medium and large. By default, the badge is set to medium.
You can change the size by adding matBadgeSize to the host element.
<div matBadge="1" matBadgeSize="large" class="demo-section">Text with large badge</div>
The badge visibility can be toggled programmatically by defining matBadgeHidden.
<button mat-raised-button matBadge="7" [matBadgeHidden]="hidden" (click)="toggleBadgeVisibility()">
Hide
</button>
Badges can be colored in terms of the current theme using the matBadgeColor property to set the
background color to primary, accent, or warn.
<mat-icon matBadge="15" matBadgeColor="warn">home</mat-icon>
Badges should be given a meaningful description via matBadgeDescription. This description will be
applied, via aria-describedby to the element decorated by matBadge.
When applying a badge to a <mat-icon>, it is important to know that the icon is marked as
aria-hidden by default. If the combination of icon and badge communicates some meaningful
information, that information should be surfaced in another way. See the guidance on indicator
icons for more information.