relative time in redux reactjs - reactjs

Question

I have some data with datetime fields , i want to show the relative date time using momentJS fromNow(). However after the initial load it shows timestamp as a few seconds ago. But this will not be updated until a next state change triggered. Is it a good practice to keep another state in the state-tree & control via a timer function setInterval in componentDidUpdate?
render()
{
// get the new prop value here which triggered from a setInterval -> action -> reducer -> state change -> propagate to connected components
const text = comment.get('text');
const dateTime = moment(comment.get('dateTime')).fromNow();
return (
// add the new prop into the component
<div key={id}>
<Comment
text = {text}
dateTime = {dateTime}
</div>
}

Answer 1

I scribbled down a component that takes an epoch time timestamp and display a momentjs text for it.
The text is updates via inner component state every 300ms which you can change however you'd like.
You can notice on this fiddle, every new text is logged in the console. After 45 seconds you should see the text change from "a few seconds ago" to "a minute ago".
Fiddle here, this is the code:
var MomentTime = React.createClass({
getInitialState: function() {
return {text: ""};
},
componentWillMount: function() {
this._updateMomentText();
this.interval = setInterval(this._updateMomentText, 300);
},
componentWillUnmount: function() {
clearInterval(this.interval);
},
_updateMomentText: function() {
var text = moment(this.props.timestamp).fromNow()
console.log(text)
if(text !== this.state.text) {
this.setState({text: text});
}
},
render: function() {
return <div>{this.state.text}</div>;
}
});
ReactDOM.render(
<MomentTime timestamp={new Date().getTime()} />,
document.getElementById('container')
);