how to see if a web site is useing react

if(!!window.React ||
!!document.querySelector('[data-reactroot], [data-reactid]'))

if(!!window.angular ||
!!document.querySelector('.ng-binding, [ng-app], [data-ng-app], [ng-controller], [data-ng-controller], [ng-repeat], [data-ng-repeat]') ||
!!document.querySelector('script[src*="angular.js"], script[src*="angular.min.js"]'))

if(!!window.Backbone) console.log('Backbone.js');
if(!!window.Ember) console.log('Ember.js');
if(!!window.Vue) console.log('Vue.js');
if(!!window.Meteor) console.log('Meteor.js');
if(!!window.Zepto) console.log('Zepto.js');
if(!!window.jQuery) console.log('jQuery.js');

how to read if a person has send a message on discord.js

client.on('message', message => {
// this function can check whether the content of the message you pass is the same as this message
let filter = msg => {
return msg.content.toLowerCase() == message.content.toLowerCase() && // check if the content is the same (sort of) ==; // check if the author is the same
}, {
maxMatches: 1, // you only need that to happen once
time: 5 * 1000 // time is in milliseconds
}).then(collected => {
// this function will be called when a message matches you filter