import { valueConverter } from 'aurelia-framework';

@valueConverter('pluralise')
export class PluraliseValueConverter {
    toView(value: number, text: string): string {
        return value > 1 ? `${text}s` : text;
    }
}

import { valueConverter } from 'aurelia-framework';

@valueConverter('pluralise')
export class PluraliseValueConverter {
    toView(value: number, text: string): string {
        if (value > 1) {
            return `${text}s`;
        } else {
            return text;
        }
    }
}

--- 
+++ 
@@ -3,10 +3,6 @@
 @valueConverter('pluralise')
 export class PluraliseValueConverter {
     toView(value: number, text: string): string {
-        if (value > 1) {
-            return `${text}s`;
-        } else {
-            return text;
-        }
+        return value > 1 ? `${text}s` : text;
     }
 }
Use ternary operator in PluraliseValueConverter
