Function context refers to the value of this within a function.
this keyword determines which object a function operates on, and it depends on how the function is called.

If a function is called without an object (like a regular function), this refers to the global object (window in browsers, global in Node.js). In strict mode, this will be undefined in a standalone function.

function showContext() {
  console.log(this);
}
showContext(); // window / global / undefined

When a function is called as a method of an object, this refers to the object that called the method:

const user = {
  name: "Jack",
  getName() {
    console.log(this.name);
  }
};
user.getwName(); // "Jack"

When a function is used as a constructor (called with new), this refers to the newly created instance of the object.

function Person(name) {
  this.name = name;
}
const person = new Person("Tom");
console.log(person.name); // "Tom"

Arrow functions don't have their own this context. Instead, they refer to this from the surrounding lexical scope.
This is useful for ensuring that this remains the same inside nested functions.

const user = {
  name: "Jack",
  showName: () => {
    console.log(this.name);
  }
};
user.showName(); // undefined

Above this refers to the global object (which is window in a browser or {} / global in Node.js).

Unlike regular functions, arrow functions "inherit" this from the scope where they were defined, not where they are called.

• The Definition Scope: You defined showName inside an object literal. However, an object literal does not create a new scope - a set of curly braces {} used to create an object does not create a new "this" context, only functions and classes do that.

• The Outer Scope: Because the object doesn't have a scope, the arrow function looks one level higher to the Global/Module scope.

• The Result: At the global level, this points to the global object. Since there is likely no global variable named name, it returns undefined.

You can manually set the function context with methods like .call(), .apply(), or .bind().

function showName() {
  console.log(this.name);
}
const user = { name: "Sarah" };
showName.call(user); // "Sarah"