title: Understanding typescript syntax in Angular 4
body: <p>I am new to Angular 4 and Typescript. I followed the "Angular-tour-of-heroes" tutorial available in Angular.io website. Since Angular 4 uses typescript for defining components etc., I wanted to understand more about typescript, so I looked for documentation in internet. I got further confused when I read the documentation for typescript available at '<a href="http://devdocs.io/typescript/" rel="nofollow noreferrer">http://devdocs.io/typescript/</a>'. When I compared the syntaxes given in the documentation and Angular code, I found a lot of differences. </p>
  
  <p>1) Functions are declared with 'function' keyword, but in Angular, function is not declared with 'function' keyword.</p>
  
  <p>2) Types are declared using 'let' keyword in documentation, but in Angular there is no 'let' keyword. </p>
  
  <p>There are many differences like this. So, I am confused about where to look for the documentation for TypeScript ( and why Angular uses a different syntax.</p>