mutludev

How Axios Processes Interceptors Order Matters

2025-05-27T00:00:00Z

If you’ve written any frontend app with authentication, you've probably used Axios interceptors. But have you ever thought about the order in which they run? I hadn’t, until I ran into a bug (or maybe a feature).

While setting up my refresh token logic, I created two request interceptors like this:

instance.interceptors.request.use(refreshTokenInterceptor);
instance.interceptors.request.use(authenticationTokenInterceptor);

refreshTokenInterceptor checks if the token is expired and, if it is, fetches a new one from the server and saves it to localStorage.

authenticationTokenInterceptor then takes the token from localStorage and attaches it to the request.

Well, when I tested it, the token was getting refreshed, but the request was still being sent with the old token. After a few console.logs, I figured out the issue: request interceptors run in reverse order to how they’re defined.

After a quick Google search, I found this is a known behavior in Axios:

Axios states that request interceptors are stack-based; they run like popping from a stack.

I'm still not sure if this is a bug or a feature, but it doesn’t look like it’ll change anytime soon. So next time you add more than one interceptor, keep this in mind.

Git Tips Exclude files locally

2025-05-16T00:00:00Z

Recently, I ran into an annoying issue while working on a project. The repository has a configuration file that's checked into Git, but I need to modify it to suit my development environment. Unfortunately, since the file is tracked, Git constantly flags it as modified. Every time I want to pull new changes, I have to stash and pop my local changes, and it becomes annoying fast.

Fortunately, Git has a local exclude file that can help. Here's how to use it:

Open the .git/info/exclude file in your repository.
Add the path to the file you want Git to ignore, just like you would in a .gitignore file.

That’s it. Git will now locally ignore changes to that file. This tip really worked for me, so I'm sharing it here in case it works for you as well, and in case I need it in the future.

Weird behaviors of javascript Primitive Types and Reference Types

2023-05-26T00:00:00Z

I recently learned a difference between Primitive types and Reference types. I thought it would be great to write a blog post about this topic.

Let's start with a code snippet

let a = 1;
let b = a;

console.log(b); // 1

a = 2;

console.log(b); // 1

Well this looks okay let's do the same thing with an object

let a = {
	someText: "Hello",
};

let b = a;

console.log(b); // { someText: "Hello" }

a.someText = "Hi";

console.log(b); // { someText: "Hi" }

This performed unexpected isn't it? You will understand why this happens by the end of this post, let's dive into it.

What are primitive and reference types

In Javascript, we have 6 primitive types

String
Number
Boolean
null
undefined
Symbols (ES6)

and 3 Reference types

Object
Array
Function

Primitive types

Primitive types stored in a fixed-sized memory, so exact value of "a" stored in memory, I think an example would be more helpful here

We created variable "a", it placed into memory like this

then we copied memory value of variable "a" to variable "b"

That seems okay let's see what happens with Reference types

Reference Types

Reference types are more complex and take up more space compared to Primitive types. They can't be stored in fixed memory so they stored in a random location in memory let's see it's diagram

Notice that the value stored in memory is not the real value itself, its reference to real value. When we copy the variable "a" to "b" we copy the Memory value (Reference to real object). That's why they're called reference values. When we copy the variable "a" we don't copy the real value, we copy reference to real value.

That's why "b" is also changed when we change the property of "a".

Source

https://github.com/leonardomso/33-js-concepts
- Section 3. Value Types and Reference Types

Thanks for reading

Making git more productive with aliases

2020-08-27T00:00:00Z

What is an alias

This would be a quick tutorial. If you ever checked your .bashrc file probably saw the alias keyword. Creating alias in bash is like creating shortcut for command so instead of typing git status you can type gs and run the same command.

Creating new alias

Let's create an alias for git status command.

Open your .bashrc file, you can use any text editor
Add alias gs="git status" to end of the file
- Let's inspect our code
- alias - keyword
- gs - shortcut
- git status - full command

Example configuration that i use

alias gs="git status"
alias ga="git add -A"
alias gp="git push"

Ending

You can use aliases for every command. So be creative. If you find yourself typing the same command over and over again try making it shorter. Thanks for reading this post.