license import { Directive , Input } from '@angular/core' ; let nextUniqueId = 0 ; /** Hint text to be shown underneath the form field control. */ @ Directive ( { selector : 'mat-hint' , host : { 'class' : 'mat-hint' , '[class.mat-right]' : 'align == "end"' , '[attr.id]' : 'id' , '[attr.align]' : 'null' , } } ) export class MatHint { /** Whether to align the hint label at the start or end of the line. */ @ Input ( ) align : 'start' | 'end' = 'start' ; /** Unique ID for the hint. Used for the aria-describedby on the form field control. */ @ Input ( ) id : string = `mat-hint-${ nextUniqueId ++ }` ; }