import { Injectable, Pipe, PipeTransform } from '@angular/core'; @Pipe({ name: 'startsWith', }) @Injectable() export class StartsWithPipe implements PipeTransform { transform(items: T[], field: string, value: string): T[] { if (!items) { return []; } if (!value || value.length === 0) { return items; } return items.filter(it => it[field] && it[field].toLowerCase()[0] === value); } }