Understanding the file architecture of a web app

Hey everyone,

I’m not entirely certain what to call this so, please bear with my meandering explanation.

I have been added to a group of freelancers to work on a WeChat app over the next few months, a lot of it is written with React and a bit of Vue.js.

Opening up the repo, there are well over 100 different files, index.html’s, component.js’, etc.

While I do understand the individual components and functions within each file, I have not a single clue as to how or where the data is coming from and how the files are conversing with each other.

Question time, what is this interaction called? If a function is a block of code, a method a pre-built function, and a program a collection of functions and methods to bring about an action or result, what is that conversation this collection of files/programs that each have their own tasks but interact with each other as well called?

I need to get a better handle on how this is all supposed to be interacting so I can contribute more fully and the first step is finding a name to this current problem.

Thanks in advance.

I guess you can refer to them as “modules”, or if it’s bigger maybe even “system” ?

UPDATE: https://en.wikipedia.org/wiki/System_software