Type Checking an Interface with Custom User-Defined Type Guard
Explore how to implement custom user-defined type guards in TypeScript to check interface structures without altering types. Learn to use the in operator for property checks and understand how these methods help TypeScript narrow union types, enhancing code reliability and type safety.
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We'll cover the following...
User-defined function
A custom user-defined type guard is a function that checks specific parts of the structure of an object to determine if it is one type or another. The advantage is that the type does not need to be altered with a branded property or used with a discriminator. However, it comes with the cost of foregoing functions that check every type.
The following code has a function on line 21 which takes a single ...