Understanding and Implementing Type Guards in TypeScript

What are Type Guards in TypeScript?

TypeScript is an object-oriented programming language that is based on JavaScript. As such, it has a lot of features that are not found in other languages. One of these is the concept of type guards. Type guards are a way to ensure that a certain type of value is being used in a particular piece of code.

A type guard is a special function or statement which can be used to check the type of a given value. This type check is performed at the time of compilation and the code will not compile if the type of the value doesn't match. Type guards can be used to ensure that types are correct when performing any kind of operation, such as loops and conditionals.

Type guards also make sure that errors occur only when they should, as opposed to when they shouldn’t. This means that any type errors are caught before the program is executed, meaning that it can be resolved much easier than if they were caught while the program was running.

Type guards can be used in a variety of situations, such as when writing classes, interfaces and functions. They can help ensure that values are of the correct type and can help to prevent errors from occurring due to unexpected types. Type guards can also be used to test the types of values that are returned from functions and methods.

Type guards are an important part of writing reliable TypeScript code and should be used wherever possible to ensure that code is robust and free of errors.