As we are in TypeScript, the TypeScript string type should be used.
Spaces are also the key for a readable piece of code.

https://stackoverflow.com/questions/14727044/what-is-the-difference-between-types-string-and-string

var str: String = new String("Hello world"); // Uses the JavaScript String object

var str: string = String("Hello World"); // Uses the TypeScript string type

What is the difference between type String vs. string?