TypeScript is 4.9.4 What’s new?

Introduction

TypeScript is a popular programming language that is a superset of JavaScript. It adds optional static typing and other features to JavaScript, allowing developers to write type-safe code and catch errors at compile time. The latest version of TypeScript is 4.9.4, which includes several new features and improvements.

New Features

One of the major new features in TypeScript 4.9.4 is support for the unknown type. This is similar to the any type, but it provides additional type-safety by requiring explicit type assertions before using a value of type unknown. This helps prevent errors caused by using values without checking their type.

Another new feature in TypeScript 4.9.4 is the ability to use unknown and never as type arguments. This allows you to write more precise and expressive types, and helps the TypeScript compiler catch errors in your code.

Another improvement in TypeScript 4.9.4 is better support for type checking of functions. The type checker now considers the return type of a function when checking the type of its this value. This allows you to write more accurate and safe code, and helps the compiler catch errors.

Conclusion

TypeScript 4.9.4 includes several new features and improvements that make it even more powerful and useful for writing type-safe code. The addition of the unknown type and improved support for type checking of functions are particularly significant, and will help developers write safer and more accurate code.