poll-interval

poll.js

import React from 'react';

export class MyComponent extends React.Component {
  constructor(props) {
    super(props);
    this.state = {
      items: [],
  }
  
  componentDidMount() {
    this.poller = setInterval(() => this.callMyPollEndpoint(), 3000);
  }

  componentWillUnmount() {
    this.poller = null; // clean up
  }

  callMyPollEndpoint = () => {
    fetch('/my-poll-endpoint')
      .then(result => result.json())
      .then(result => this.setState({ items: result }));
  }
  
  render() {
    const { items } = this.state;
    return (
      <div>
        {items.map((obj) => obj}
      </div>
    );
  }
}

export default MyComponent;