JSFiddle - React, Tailwind, and code Playground

HTML

<button>click</button>

JavaScript

const button = document.querySelector('button');

function foo() { console.log('button clicked', this) }

button.addEventListener('click', foo);

/****/

const obj = {
  method: function (cb) {
  	console.log('method', this);
    
    return cb();
  }
};

obj.method(function() { console.log('cb', this) });