author: Krasimir Tsonev

Hi there, I'm . Senior front-end engineer with over 13 years of experience. I write, speak and occasionally code stuff. Follow me on Twitter, GitHub, Facebook or LinkedIn

Get to know Kent C. Dodds

posted in Inspiration on 2021-10-05   , ,

A short movie for Kent C. Dodds.

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White-labeling React apps

posted in JavaScript on 2021-08-16   , ,

A white label app is an app that we build once and "resell" it to other people/companies. Very often we are talking about applying different themes but sometimes we have to change logic too. Such changes should be as declarative as possible so they scale well. Otherwise is more of a copy/paste exercise. In this article I want to sketch out a couple of approaches for white labeling in React applications.

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Firebase/GCP: save money by cleaning up your artifacts

posted in JavaScript on 2021-06-06   , ,

I'm working on a personal project and I'm using the awesome Google Cloud Platform. There are so many things that you can do. All the tools that you may need are probably there. This of course comes with a price. In this article I'll share a tip how to reduce your spendings there.

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Using JavaScript module system for state management

posted in JavaScript on 2021-03-08   , ,

Hot topic last couple of years is state management. Especially in the front-end apps. There are lots of problems and lots of solutions. One thing thought is totally ignored in this context - the JavaScript module system. I'm very often reaching out to this approach and decided to share it here.

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Miss Piggy - a test runner for Puppeteer

posted in JavaScript on 2021-02-01   , ,

These days I did (again) a bunch of changes in Google tag manager. This time however was more of a refactoring exercise. So, I had to prove that the tags that were placed before the refactoring exist after the refactoring. And what we programmers do in such cases - we write tests.

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Configure Google domain email in Vercel with ImprovMX

posted in Architecture on 2021-01-27   , ,

Back in February last year I blog on topic Email not working after DNS change. Well, I had kinda similar situation but not exactly. This time I bought a domain from Google and wanted to use an email with it. The setup wasn't obvious for me so I decided to document the process.

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Reinventing the routing in React apps

posted in JavaScript on 2021-01-18   , ,

The router is the backbone of your application. Trust me, that's how it is and I can prove it. One of the fundamental ideas in Web is the URL (Uniform Resource Locator). Or the way of how we very often call it - "web address". No mather what you are building there is a web address which identifies your resource. The router is the front office that accepts the request to particular URL and wires it to a logic. Logic for generating HTML or JSON response or something else. So, the router is very important part of your system.

At the end of last year I rewrote one of my favorite projects - a vanilla JS router called Navigo. I was procrastinating this work for years. Finally I did it in TypeScript and wrote 100+ unit tests along the way. This refactoring opens the door for new features and more importantly, for integrating the library into other places. Like React for example.

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Transpile to ES modules with Babel

posted in JavaScript on 2021-01-14   , ,

While I was working on Navigo an issue popped out. It was about using the library in the context of Web Dev Server where we have everything in TypeScript. And something was not ok with Navigo. The npm package wasn't exported properly and we were keep getting a does not provide an export named 'default' error. It turned out the problem is that Navigo is not exported properly as ES module (also known as ESM).

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Mocking console methods with Jest

posted in JavaScript on 2021-01-01   , ,

I'm recently working on two OS libraries. Both I'm unit testing with Jest. There is some logic that leads to a warning which I'm doing with console.warn. In the unit tests this is happening quite often so I want to suppress it. Also I want to verify that it happens on the right place.

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Copy files and directories from and to Kubernetes pods

posted in Architecture on 2020-12-11   , ,

At work we have a project that uses node:10-jessie image as a base for its docker container. That image has no vi inside so I wondered how to check the content of a file. Luckily kubectl has a neat command to copy files from and to a pod.

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