Why is TypeScript not inferring the type correctly?

Question

typescript

There is a request through the prisma library that returns a value with the User[] type. Why do I get a variable of type User and not User when I get element with index 0 from this array | undefined? The array can be empty.

Answer 1

Because, in fact, under the hood is this type:

type Array<T> = {
  length: number;
  [i: number]: T;
} & ArrayMethods<T>;

where ArrayMethods is the description of the methods from the prototype