ts-migrate VS mocha

Airbnb converted many millions of lines gradually using automation and wrote about it:

https://medium.com/airbnb-engineering/ts-migrate-a-tool-for-...

And also open sourced the tooling:

https://github.com/airbnb/ts-migrate

Are you migrating with ts-migrate?

When you migrate your entire project over to TypeScript, errors like "undefined is not a function", syntax errors, or reference errors should no longer exist in your codebase. Thankfully, this is not as daunting as it sounds. Migrating your entire Node.js application to TypeScript can be done incrementally so that you can start reaping the rewards immediately in crucial parts of the codebase. You can also adopt a tool like ts-migrate if you intend to perform the migration in one go.

Flow to ts — helps to produce raw migration from Flow to TS files and reduces monkey job. TS migrate — helps convert JS files to Typescript files. A great introduction can be found here.

💡 I typed it using ts-migrate ts-migrate is a tool I strongly recommend. It's been developed by Airbnb to help to migrate easily JavaScript projects to TypeScript.

When you decide to migrate, I recommend checking https://github.com/airbnb/ts-migrate may speed few migration steps (but it wont solve missing types/interfaces)

You can use AirBnb's ts-migrate tool or try a more direct tactic following the Migrating from JavaScript guide.

Take a look at https://github.com/airbnb/ts-migrate

When you migrate your entire project over to TypeScript, errors like "undefined is not a function", syntax errors, or reference errors should no longer exist in your codebase. Thankfully, this is not as daunting as it sounds. Migrating your entire Node.js application to TypeScript can be done incrementally so that you can start reaping the rewards immediately in crucial parts of the codebase. You can also adopt a tool like ts-migrate if you intend to perform the migration in one go.

Using something like Vitest, Jest, or Mocha didn't work because:

MochaJS is a feature-rich JavaScript test framework running on Node.js, making it a popular choice for both backend and frontend testing. It's known for its flexibility and straightforward syntax, allowing for asynchronous testing and the use of any assertion library.

We use Jest Framework for testing. Jest is not a dogma, and, of course, in its place can be any other test runner, such as Mocha or Ava. Let's focus on tests. I'll provide a short example because I don’t want to waste your time. You can find the full version here. It's crucial to read the comments in the code below. Let's go!

JavaScript Popular tools for testing: Mocha, Jasmine, Unit JS, Jest

To execute your tests, you can create test scripts using popular testing frameworks like Mocha, Jasmine, or Jest. These frameworks provide a structured way to organize and run your tests, report results, and handle assertions.

⚗️ Mocha and Chai for testing

Testing frameworks like Jest, Mocha, and Jasmine are crucial for software development, ensuring code reliability and correctness. They offer features like test suites, test cases, assertions, and asynchronous testing support.