devBlog of Michal Zalecki

Register .test domain with ENS

Cee, five, ef, dee, ef, four, ow, six, seven, oh wait, it’s ow, seven, six, bee… That’s of course not the way you would like to share your Ethereum address or Swarm and IPFS content hash. You copy and send it or scan QR codes but this experience is still inferior to using easy to remember, readable names. In the same way, as DNS solved this problem for IP addresses, ENS has a goal of mitigating this issue in Ethereum ecosystem.

How to verify smart contract on Etherscan?

Why would you like to verify your smart contract? It depends. It mostly depends on your use case. It always comes down to being transparent. If I were into ICOs, I would want to make sure that the token and the crowdsale contract code enforces cryptoeconomics described in the whitepaper (or, ugh…, in the video). Open sourcing the code on GitHub is a great idea but gives no guarantees that the code in the repository is even remotely similar to the one running on-chain. It is a contract after all so it would be good to give other parties a chance to familiarize with the conditions they are going to “sign”. Verify the source code even if not everyone has programming skills to read it.

Docker Compose for Node.js and PostgreSQL

Docker is the response to an ongoing problem of differences between environments in which application runs. Whether those differences are across machines of the development team, continuous integration server, or production environment. Since you are reading this, I assume you are already more or less familiar with benefits of containerizing applications. Let’s go straight to Node.js specific bits.

Deploying smart contracts with Truffle

Truffle provides a system for managing the compilation and deployment artifacts for each network. To make an actual transaction and put a smart contract on-chain we have to provide Truffle with an appropriate configuration. We configure each network separately. From this post, you will learn how to prepare a setup and deploy to a few widely used test networks.

Ethereum: Test-driven development with Solidity (part 2)

This is the second part of the test-driven introduction to Solidity. In this part, we use JavaScript to test time-related features of our smart contract. Apart from that, you will see how to check for errors. We will also complete the rest of the smart contract by adding withdrawal and refund features.

Ethereum: Test-driven development with Solidity (part 1)

Depends on how you count, second and third generation blockchain applications are not bound by restrictions of underlying protocols. Programmers can create smart contracts — distributed applications with access to code-controlled accounts. Use cases go far beyond exchanging value and applies where users benefit from replacing trust between parties with code.

Using Sequelize with TypeScript

Sequelize is an ORM for Node.js written in JavaScript, not TypeScript. Despite that good quality typings are available, it is not straightforward how to get up to speed with Sequelize and TypeScript. I would like to go through crucial elements and show how to maximize safety coming from static typing when using Sequelize. Let’s start with setting things up.

Convert files for the web from your terminal

For me, using a terminal is fundamental to tasks automation. I love to augment my workflow using a command line tools. One of the things I try to automate is preparing assets for using them in web apps. This post is a kind of documentation to me.

Nominal typing techniques in TypeScript

Many functional programming languages like Haskell or Elm have a structural type system. This perfectly lines in with the direction in which majority of JavaScript’ish community is heading. Nevertheless, every feature comes with a certain set of trade-offs. Choosing structural type system allows for a greater flexibility but leaves a room for a certain class of bugs. What I find interesting is that the answer to the question whether TypeScript, Flow or any other type system adopts structural or nominal type system does not have to be binary. So, is it possible to have the best of both worlds writing in TypeScript?

Testing redux-thunk like you always want it

Redux Thunk is one of the most if not the most popular Redux middleware with over 2 million downloads a month. If you compare this number to the Redux 4 million downloads a month, it is easy to figure out that over half of Redux projects are using Redux Thunk. As the name “thunk” suggests, the main goal of Redux Tunk is to allow for lazy evaluation (dispatching) of actions. While this makes it possible to dispatch actions in an asynchronous manner, it also makes it harder to test.

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