What is 'this' keyword in JavaScript?

In JavaScript, the this keyword refers to the object that the function is a property of. It can also refer to the global object if the function is not a property of any object. The value of this is determined at the time the function is called, not at the time the function is defined.

The value of this can be explicitly set using the call() or apply() methods of a function, or by using the bind() method to create a new function with a specific value of this.

Arrow functions, introduced in ES6, behave differently than regular functions when it comes to the this keyword. In an arrow function, the value of this is inherited from the surrounding context, and cannot be changed.