Classes Documentation You can create a greeter by instantiating the Greeter

this and arrow functions In JavaScript, this is a variable that’s set when a function is called. This makes it a

Use Union Types Don’t write overloads that differ by type in only one argument position:

Install our dependencies Now we can use npm install to install packages. First install TypeScript and gulp globally. (You might

Readonly properties Some properties should only be modifiable when an object is first created. You can specify this by putting readonly

Integrating with Build Tools You might have some more build steps in your pipeline. Perhaps you concatenate something to each of your files

Use Optional Parameters Don’t write several overloads that differ only in trailing parameters:

Static Properties Up to this point, we’ve only talked about the instance members of the class, those that show up on the object when

Optional Parameters in Callbacks Don’t use optional parameters in callbacks unless you really mean it:

Re-declarations and Shadowing With var declarations, we mentioned that it didn’t matter how many times you declared your variables;