react-script-loader.jsx

import React from 'react'

class ScriptLoader extends React.Component {
  state = {
    loaded: false 
  }
  
  componentDidMount() {
    const script = document.createElement('script')
    
    script.src = 'http://example.script/src'
    
    script.onload = () => {
      this.setState({ loaded: true })
    }
    
    document.head.appendChild(script)
  }
  
  render() {
    if (!this.state.loaded) {
      return null
    }
    
    return <SomeComponent />
  }
}