AsciiLoadingIndicator.js

import React from 'react'

const loaders = ['⣾', '⣽', '⣻', '⢿', '⡿', '⣟', '⣯', '⣷']

export default class AsciiLoadingIndicator extends React.Component {
  state = {
    loaderIndex: 0
  }

  componentDidMount () {
    this.loaderChangeInterval = window.setInterval(() => {
      this.setState((prevState) => {
        return {
          loaderIndex: (prevState.loaderIndex + 1) % loaders.length
        }
      })
    }, 300)
  }

  componentWillUnmount () {
    window.clearInterval(this.loaderChangeInterval)
  }

  render () {
    return <span>{loaders[this.state.loaderIndex]}</span>
  }
}