Why is contentLength a string instead of a number?

[TheBrunoRM]

I am wondering why the contentLength property from the videoFormat interface is declared as a string instead of as a number, as it is being used throughout the code only as a number. Is there any reason for this?

I am talking about this

node-ytdl-core/typings/index.d.ts

Line 43 in 99e6c67

contentLength: string;