This keyword

In JavaScript, this keyword refers to the object to which it belongs. It has different values depending on where it is used.

• Alone, this refers to the global object

console.log(this) // window

• In a function with a strict mode, this equals an undefined

"use strict"
function fn() {
  console.log(this); // undefined
}

• In a function, this refers to the global object

function fn() {
  return this;
}
console.log(fn()); // window in non-strict mode, undefined in strict mode

• In an arrow function, this refers to the parent scope

const fn = () => {
  console.log(this); // window. Takes this from parent scope
}

• In an object method , this refers to the object

const obj = {
  name: "hello",
  fn: function () {
    console.log(this.name);
  },
};
obj.fn(); // hello