About
Type assertions gives type information to typescript generally to details the type information of an any variable type.
It does not perform any special check or restructuration of data such as a type cast.
Syntax
angle-bracket
The “angle-bracket” syntax:
let someValue: any = "this is a string";
let strLength: number = (<string>someValue).length;
as-syntax
let someValue: any = "this is a string";
let strLength: number = (someValue as string).length;