JSFiddle - React, Tailwind, and code Playground

JavaScript

function Color() {
  this.color = 'red';
  this.getColor = function getColor() {
    console.log(this.color);
  };
}

const b = new Color();
b.color = 'blue';
b.getColor();

// function AnotherColor() {
//   this.color = 'red';
//   this.getColor = function getColor() {
//     return setTimeout(() => console.log(this.color), 2000);
//   };
// }

function AnotherColor() {
  this.color = 'red';
  this.getColor = function getColor() {
    const self = this;
    return setTimeout(function () {
      console.log(self.color);
    }, 2000);
  };
}
const c = new AnotherColor();
c.color = 'green';
c.getColor(); // green