5 TypeScript Libraries to Improve Your Codebase

Increase your confidence in static typing

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The TypeScript language has done anything but grow in the past years. It has been rated as the favorite language for many web developers. It is becoming less and less frequent to have to be working in a plain JavaScript codebase.

However, sometimes TypeScript is not used to its fullest potential. Too many castings or the use of any are amongst the most frequent mistakes.

In this article, we will see a list of libraries that will enhance your TypeScript experience and increase your confidence in its static typing. Those minimal libraries will boost any developer's ergonomics.

1. zod

The weak link of TypeScript is that is only validated at compile time. Once it is parsed and built, all types are removed. That might lead to some undesired bugs when:

• the compiler is trusting the developer with some assumptions (use of any, ts-expect-error, casting, etc…)
• the network is returning a different REST schema than expected.

Let’s see an example of the latter:

In the above code, the compiler is trusting that the network will be returning a JSON User object with a name and email properties. If that turns out not to be true we will be facing some problems in production. Unfortunately, that can only be found at runtime.

With zod we can define a schema that will be also validated at runtime.

Let’s see a refactor of the previous code with the usage of zod

We can choose how we deal with errors. In the above example the UserSchema.parse will throw an error at runtime.