Moment.js with ReactJS (ES6)

Since you are using webpack you should be able to just import or require moment and then use it:

import moment from 'moment'

...
render() {
    return (
        <div>
            { 
            this.props.data.map((post,key) => 
                <div key={key} className="post-detail">
                    <h1>{post.title}</h1>
                    <p>{moment(post.date).format()}</p>
                    <p dangerouslySetInnerHTML={{__html: post.content}}></p>
                    <hr />
                </div>
            )}
        </div>
    );
}
...