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13 posts tagged with "JavaScript"

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Non-root containers in Kubernetes

· 2 min read
Matej Jelluš
IT enthusiast that loves to write code and trying new things. Currently working in Bratislava as CTO in Kontentino.

Container should be able to perform only a very limited set of operations and it is highly recommended to use different user from root. To achieve this both docker file and kubernetes config must be changed.

Run simple Node.js application in Kubernetes cluster

· 8 min read
Matej Jelluš
IT enthusiast that loves to write code and trying new things. Currently working in Bratislava as CTO in Kontentino.

Write simple Node.js backend using TypeScript, Express and Terminus and run it in Digital Ocean Kubernetes cluster. In the end you will have application which is running in multiple replications and has access to environment variable passed to the application by Kubernetes secret.

Publish NPM package with GitHub Actions

· 3 min read
Matej Jelluš
IT enthusiast that loves to write code and trying new things. Currently working in Bratislava as CTO in Kontentino.

On couple of my projects, I started using GitHub Actions. I also wanted to use it for pentest-tool-lite, where I want to run TypeScript lint after each push and publish it to npm after release is created. I had some problems which I recently solved, so I am sharing my solution.

Javascript, the weirdo

· One min read
Matej Jelluš
IT enthusiast that loves to write code and trying new things. Currently working in Bratislava as CTO in Kontentino.

Collection of JavaScript examples when it behaves...weird? Funny?

React and setState method

· 3 min read
Matej Jelluš
IT enthusiast that loves to write code and trying new things. Currently working in Bratislava as CTO in Kontentino.

The first thing you read about setState - it is asynchronous. I understand it but still did not realize a couple of things.

Please, do not install every shit

· 2 min read
Matej Jelluš
IT enthusiast that loves to write code and trying new things. Currently working in Bratislava as CTO in Kontentino.

I am working on React app with couple of other developers. And you know it, you need this component, that functionality, etc. so you google it, install the package and the work is done. Is it ok to work like this? Do you even know what exactly you added to your project and do you really need it?

Chaos Ajax - is your application ready to fail?

· 3 min read
Matej Jelluš
IT enthusiast that loves to write code and trying new things. Currently working in Bratislava as CTO in Kontentino.

You are creating an application that shows data to the user - doesn't matter if he is searching for some specific thing or he is only listing everything you have. What happens if the server responds with empty array? Or with error? Will your application show only empty space or an error message?

Introduction to Sequelize ORM

· 8 min read
Matej Jelluš
IT enthusiast that loves to write code and trying new things. Currently working in Bratislava as CTO in Kontentino.

This is about the basic usage of Sequelize ORM – how to create migrations, models, seeders and how to get the data from the database. Everything is explained on an example project, which you can find on GitHub.

Google Code Jam 2017: Oversized Pancake Flipper

· 5 min read
Matej Jelluš
IT enthusiast that loves to write code and trying new things. Currently working in Bratislava as CTO in Kontentino.

Last year, the Infinite House of Pancakes introduced a new kind of pancake. It has a happy face made of chocolate chips on one side (the “happy side”), and nothing on the other side (the “blank side”).

You are the head cook on duty. The pancakes are cooked in a single row over a hot surface. As part of its infinite efforts to maximize efficiency, the House has recently given you an oversized pancake flipper that flips exactly K consecutive pancakes. That is, in that range of K pancakes, it changes every happy-side pancake to a blank-side pancake, and vice versa; it does not change the left-to-right order of those pancakes.

You cannot flip fewer than K pancakes at a time with the flipper, even at the ends of the row (since there are raised borders on both sides of the cooking surface). For example, you can flip the first K pancakes, but not the first K – 1 pancakes.

Your apprentice cook, who is still learning the job, just used the old-fashioned single-pancake flipper to flip some individual pancakes and then ran to the restroom with it, right before the time when customers come to visit the kitchen. You only have the oversized pancake flipper left, and you need to use it quickly to leave all the cooking pancakes happy side up, so that the customers leave feeling happy with their visit.

Given the current state of the pancakes, calculate the minimum number of uses of the oversized pancake flipper needed to leave all pancakes happy side up, or state that there is no way to do it.

Express server with JWT authentication

· 10 min read
Matej Jelluš
IT enthusiast that loves to write code and trying new things. Currently working in Bratislava as CTO in Kontentino.

I needed to create a simple server, that would have one “public” route /login and other routes are available only for users with valid JWT token.

That means, the user is allowed to log into the system and then get any data from it. If he is not logged in and he tries to get some data, he only get an error message and 401 ( Unauthorized ) status code will be returned.