Hands-On Functional Programming with TypeScript

The this operator in the global context

In the global context, the this operator will always point to the global object. In a web browser, the window object is the global object:

console.log(this === window); // truethis.a = 37;console.log(window.a); // 37console.log(window.document === this.document); // trueconsole.log(this.document === document); // trueconsole.log(window.document === document); // true

The preceding example should be implemented using JavaScript. The preceding code will fail in TypeScript if the strict compilation flag is enabled because the strict flag enables the noImplicitThis flag, which prevents us from using the this operator in a scope in which its value is not clear, such as a global scope.