Keyword "this". JavaScript.

keywordthis.js

"use strict";

console.log(this); //undefined

function Person(name, age) {
  this.name = name;
  this.age = age;
  this.sayName = () => {
    console.log(this.name);
  };
}

/* 
  The "new" operator lets developers create an instance 
  of a user-defined object type 
*/

const person = new Person("Mikita", 25);

person.sayName(); // "Mikita"

const tree = {
  age: 200,
  sayAge: function() {
    console.log(this.age);
  }
};

tree.sayAge(); // 200

tree.sayAge.call(person); // 25

const personSayAge = tree.sayAge.bind(person);

personSayAge(); //25