insomnia/packages/insomnia-app/app/ui/components/response-timer.js

import React, { PureComponent } from 'react';
import PropTypes from 'prop-types';
import autobind from 'autobind-decorator';
import { REQUEST_TIME_TO_SHOW_COUNTER } from '../../common/constants';

@autobind
class ResponseTimer extends PureComponent {
  constructor(props) {
    super(props);
    this._interval = null;
    this.state = {
      elapsedTime: 0,
    };
  }

  componentWillUnmount() {
    clearInterval(this._interval);
  }

  _handleUpdateElapsedTime() {
    const { loadStartTime } = this.props;
    const millis = Date.now() - loadStartTime - 200;
    const elapsedTime = millis / 1000;
    this.setState({ elapsedTime });
  }

  componentDidUpdate() {
    const { loadStartTime } = this.props;

    if (loadStartTime <= 0) {
      clearInterval(this._interval);
      return;
    }

    clearInterval(this._interval); // Just to be sure
    this._interval = setInterval(this._handleUpdateElapsedTime, 100);
    this._handleUpdateElapsedTime();
  }

  render() {
    const { handleCancel, loadStartTime } = this.props;
    const { elapsedTime } = this.state;

    const show = loadStartTime > 0;

    if (!show) {
      return null;
    }

    return (
      <div className="overlay theme--transparent-overlay" aria-hidden={!show}>
        {elapsedTime >= REQUEST_TIME_TO_SHOW_COUNTER ? (
          <h2>{elapsedTime.toFixed(1)} seconds...</h2>
        ) : (
          <h2>Loading...</h2>
        )}
        <div className="pad">
          <i className="fa fa-refresh fa-spin" />
        </div>
        <div className="pad">
          <button className="btn btn--clicky" onClick={handleCancel}>
            Cancel Request
          </button>
        </div>
      </div>
    );
  }
}

ResponseTimer.propTypes = {
  handleCancel: PropTypes.func.isRequired,
  loadStartTime: PropTypes.number.isRequired,
};

export default ResponseTimer;