In JavaScript, why is the value of "this" keyword inside an arrow function determined by the context in which it was created, rather than by how it is called?
user
That's a great question! In JavaScript, the `this` keyword within an arrow function always refers to the same context as the lexical `this` in the enclosing function.

This is different from regular functions in JavaScript, where the `this` keyword can be influenced by various scoping rules. It makes more sense like this. 

In an arrow function, the only layer of context is created when the arrow function is declared. This implies that the context of an arrow function determined is based around where the function is created, not how it will be called.

In non-arrow function lexical scope, the value of 'this' is resolved when the actual function execution begins.

So, the `this` in an arrow function never becomes dynamic by its creation or identifier. But, the conditions when the arrow function is called, only become relevant if you set a different value to the 'this'. 

If nothing is positioned explicitly at runtime, then 'this' in the arrow function will seem a distinct value- along with whatever it senses back to when the arrow function was expressed. In other situations, such as raising an event handler in a DOM element, the inner program may cause the situation to bind another value to 'this'. In that scenario, 'this' inner the arrow function will still not relate to a greater context than bear a bigger reference, since it does not comprise a distinct dynamic context.
assistant
In JavaScript, why is the value of "this" keyword inside an arrow function determined by the context in which it was created, rather than by how it is called?
user
The "this" keyword in JavaScript behaves differently in arrow functions compared to regular functions due to the design decision made in ECMAScript 6 (ES6) specification, which introduced arrow functions.

In regular JavaScript functions, the value of "this" is determined by how the function is called. It can be the global object, the calling object (when using methods), or specifically set using methods like call(), apply(), or bind().

However, arrow functions were designed to provide a more concise syntax and solve a common problem developers faced with regular functions: the loss of context when passing a function as a callback or returning it from another function. In such scenarios, developers often had to save the context of "this" in a separate variable (like "self" or "that") before using it inside the nested function.

To address this issue, arrow functions were designed to capture the value of "this" from the enclosing context (usually the parent scope) where they are defined. This behavior is referred to as lexical scoping or lexical "this".

In simple terms, arrow functions adopt the "this" value from their parent scope, and this value remains constant regardless of how or where the arrow function is called. This design makes it easier to write code that relies on the correct context and prevents unexpected behavior.

Here's an example:

```javascript
const obj = {
  name: 'Object',
  regularFunc: function() {
    console.log("Regular function's this:", this);
  },
  arrowFunc: () => {
    console.log("Arrow function's this:", this);
  }
};

obj.regularFunc(); // Logs: "Regular function's this: { name: 'Object',... }"
obj.arrowFunc(); // Logs: "Arrow function's this: Window {...}" (The global object)
```

In this example, the regular function logs the "obj" object as its context, while the arrow function logs the global window object since it's executing in the global scope. The arrow function does not use the "obj" context because it retains the "this" value from where it was created, which is the global context in this case.
assistant