reading-notes

---

Project maintained by will-ing Hosted on GitHub Pages — Theme by mattgraham

The Call Stack

Call stack - is a mechanism for an interpreter to keep track of its place in a script that calls multiple functions

function greeting() {
   // [1] Some codes here
   sayHi();// runs this function
   // [2] Some codes here
}
function sayHi() {
   return "Hi!";
}

// Invoke the `greeting` function
// this runs first
greeting();

// [3] Some codes here

Whenever we invoke a function, it is automatically added to the Call Stack. Once the function has executed all of its code, it is automatically removed from the Call Stack

Since the call stack is single, function(s) execution, is done, one at a time, from top to bottom. It means the call stack is synchronous.

At the most basic level, a call stack is a data structure that uses the Last In, First Out (LIFO) principle to temporarily store and manage function invocation (call).

When a function is invoked (called), the function, its parameters, and variables are pushed into the call stack to form a stack frame. This stack frame is a memory location in the stack

A stack overflow occurs when there is a recursive function (a function that calls itself) without an exit point

In Summary a call stack:

1. It is single-threaded. Meaning it can only do one thing at a time.
2. Code execution is synchronous.
3. A function invocation creates a stack frame that occupies a temporary memory.
4. It works as a LIFO — Last In, First Out data structure.

JavaScript error messages && debugging

Type	Description
Reference errors	This is as simple as when you try to use a variable that is not yet declared you get this type os errors. the fact that this happens to let and const is called Temporal Dead Zone (TDZ).
Syntax errors	This occurs when you have something that cannot be parsed in terms of syntax
Range errors	Try to manipulate an object with some kind of length and give it an invalid length.
Type errors	Like the name indicates, this types of errors show up when the types (number, string and so on) you are trying to use or access are incompatible, like accessing a property in an undefined type of variable.

To debug your JS code, the easiest and maybe the most common way its to simply console.log()

Using Node.js with Visual Studio Code you can press the debug tab and add a configuration similar to this:

/*
Using Node.js with Visual Studio Code you can press the debug tab and add a configuration similar to this:
*/
{
  "version": "0.2.0",
  "configurations": [
    {
      "type": "node",
      "request": "launch",
      "name": "Launch Program",
      "program": "${workspaceRoot}/index.js"
    }
  ]
}

You can run the debugger by pressing F5 or pressing the green play button.

JavaScript error reference

Main Page