Introduction
This is where TypeScript “cheats” and ships with a file called lib.d.ts. This file contains ambient declarations for a whole bunch of common JavaScript constructs present in JavaScript runtimes and the DOM.
- This file is automatically included in the compilation context of a TypeScript project.
- The objective of this file is to make it easy for you to start writing type checked JavaScript code.
Modifying Native Types
If you want to be a clever clogs you can add stuff to the interfaces in
lib.d.ts by creating a global module (ie: global.d.ts
)
Example
lib.d.ts magic
The following code is only possible because of lib.d.ts. If it’s used
with the nolib
option, TypeScript doesn’t know that all JavaScript
objects have a toString
function.
var foo = 123;
var bar = foo.toString();