Typescript is a useful value addition to the JavaScript world. JavaScript can produce unexpected bugs at runtime because of the flexibility it offers. Typescript helps to catch these bugs at an early stage and save us from such headaches. Introducing this additional complexity with static typing does have enormous benefits when used in the right way.

By the right way, I mean, Typescript come with several sources of “unsoundness” with features like any, unknown, type assertionsetc. It is necessary to understand how the types work internally to use them effectively.

In this blog, I will talk about enums, const assertions…


Nice approach and clear explanation! One small correction. The wrong code snippet is attached for RenderErrorClient.js


In recent years many companies have started giving importance to building accessible apps. Open-source libraries like Headless UI are gaining a lot of popularity for their accessibility support.

In this blog, I will explain the aesthetics of design, a brief introduction about Accessibility and its necessity before diving into the best practices of Accessibility. A short table of contents is as follows:

  • Characteristics of Good design
  • Why is Accessibility important?
  • Web Accessibility standards
  • Checklist for building accessible apps
  • Accessibility tools and library

Characteristics of Good design

All companies want their products to reach as many users. The primary factor that one should mainly consider…


We often have to deal with legacy code at some point. In my organization, we have an app that uses the AngularJS framework and is not touched for quite some years. Recently, we were tasked to add a new feature to that app.

The app had quite a lot of outdated dependencies with dependencies coming from both bower.json andpackage.json. The build tool used older versions of Gulp andWebpack.

We tried to add the new feature without upgrading any of the packages, but it resulted in a lot of pain. Even a tiny change to the old AngularJS framework was tiresome.


While writing tests, it is often necessary to ensure that tests we write depict the actual user interaction. That is, what the user sees and how he/she interacts with it rather than testing implementation details. Testing implementation details or mocking various parts of the logic in unit tests often lack confidence and provides a false positive in many scenarios.

A funny tweet depicting the problems with unit tests

In GraphQL, Apollo has the MockedProvider component that one can use for writing tests. The problem with using MockedProvider is that it is different from the actual ApolloProvider and, matching the…

Aishwaryalakshmi Panneerselvam

Fullstack developer at Mercateo Gruppe

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