To use moment.js in react.
1) Install moment.js package npm install moment --save
2) Import moment in your React component 
import moment from 'moment'
Convert your timestamp (miliseconds) to date using new Date(1567485137) and use fromNow method of moment js.
moment(new Date(timestamp in milisecond).fromNow()
If you want to values as only days ago you can use from method
moment(new Date(timestamp in milisecond)).from(new Date())
Using react-moment
If you are using react-moment then use Moment component as below: 
import Moment from "react-moment";
then use as below
<Moment fromNow date={new Date(timestamp in milisecond).toJSON()} />