Relative date Pipe for Angular2 + TypeScript . Convert date or timestamp into relative date string e.g. "5 days ago" or to local date string e.g. "11/12/2016"

smart-date.pipe.ts

import { Pipe, PipeTransform } from '@angular/core';
import { DatePipe } from '@angular/common';

import { RelativeDatePipe } from './relative-date.pipe'; // https://gist.github.com/JonCatmull/e00afb1c96298a4e386ea1b5d091702a

const secondsInAday = 86400;

/*
 * Turn Date into realtive date (e.g. "5 days ago") unless date is
 * more than relativeMax days ago.
 * Support any value supported by Date() object constructor
 * 
 * Takes an relative max days argument that defaults to 10.
 * Usage:
 *   value | smartDate:relativeMax
 * Example:
 *   {{ 2016-12-09T13:13:43.572Z |  smartDate:15}}
 *   formats to: '12 days ago'
 * Example2:
 *   {{ 2016-12-09T13:13:43.572Z |  smartDate}}
 *   formats to: '27/11/2016'
*/
@Pipe({name: 'smartDate'})
export class SmartDatePipe implements PipeTransform {

    transform(dateStamp: number, relativeMax: number = 10): string {

        let timeAgoInSeconds = Math.floor((Date.now() - new Date(dateStamp).getTime()) / 1000);

        if (timeAgoInSeconds < relativeMax * secondsInAday) {
            return new RelativeDatePipe().transform(dateStamp);
        } else {
            return new Date(dateStamp).toLocaleDateString('en-GB');
        }

    }

}