Type definitions in TypeScript, how does it work?

Question

JavaScript

Hello.
I wanted to know from those who know exactly how the system works with Type Definitions?
As far as I understand, these are the files that are needed for Intelisense and Compilation of the code itself, ok, this is understandable.
Since these are files that only contain interfaces, where are the implementations themselves that should be written in .ts ?
I would be grateful for a good link to this topic about these files, how they are built, etc.
I am getting acquainted with Ts, if the question is idiotic, please do not criticize ..
At the time of writing the question, I could not find complete information about this topic that would answer this question.

Answer 1

The type definition just adds typing to an existing JavaScript implementation.

Answer 2

At the time of writing the question, I could not find complete information about this topic that would answer this question.

https://www.typescriptlang.org/docs/handbook/decla...