What is Call Stack in JavaScript

'Stack' is a data structure that is almost similar to Array but here we can't access data using the index number, we can only add or remove data from the top of the stack. JavaScript uses this data structure to manage execution contexts and control the execution of codes which is called 'Call Stack'.

👉🏻 How does it work?

🫴🏻 When we call a function, using the call stack mechanism JavaScript first creates an empty stack and then adds the function serial by as they are called, when their work is done it automatically removes that function from the stack. Let's understand this with an example:

function one(){
    console.log(1);
    two()
}
function two(){
    console.log(2);
    three()
}
function three(){
    console.log(3);
}

one()

When we run this code, the following things will happen in the following order:

1. As soon as we run the code, an empty stack will be created which is shown as anonymous.
2. The function one() will be invoked and pushed to the stack on anonymous.
3. Then in function one() it will invoke function two() ,
4. Function two() will be added to the stack over function one() ,
5. Within function two() function three() will be invoked.
6. Function three() will be added to the stack over function two().
7. As there is no function available to call in the function three(), after executing the function it will get popped off from the stack.
8. Now the work of function two() is also finished, so it will also get popped off, and then finally function one() will be popped off.

In the above procedure call stack works in javascript. We have seen in the example that the function entered at last in the stack got out first from it. So we can say that it follows the LIFO (Last In Fast Out) method. Now let's try to visualize this example with a diagram:

From the above diagram, we can easily visualize how functions are added to the stack, and then after executing they are getting popped off from the top.

With this, I'm concluding my article. If you have any queries or feedback, feel free to comment below or reach me on LinkedIn.

Thank you for reading. Happy learning 🤗🌸