Before using the Interactive Ink SDK web client-side libraries, you need to be familiar with the following concepts and tools heavily used by the web libraries.
MyScript API can be built and used thanks to other open sources libraries. Npm is used to manage those dependencies instead of managing them manually. If you are not familiar with npm, please read the related documentation. A file descriptor lists all the dependencies, then the client tool downloads and locally installs the binaries (or runnable sources).
Consider reading this Sitepoint article if the concept of polyfill is still unclear.