How is it possible that browserify can make server code run in the browser when servers need access to things like sockets?

Question

Am I simply ignorant of the features that some browsers offer or does this library use some strange workaround to implement these features?

Answer 1

Actually, it's neither nor ;-)

Basically, the simple answer is: Browserify does not bring everything into the browser, only the things that actually make sense and are feasible from a technical point of view.

E.g., you can easily have

url.format(...)

in the browser, as this means only handling objects and strings in memory, but you can not have

http.createServer(...)

since this simply does not work. Additionally to this, Browserify provides shims for require and module.exports, hence you can use CommonJS modules in the browser as well, but only as long as they stick to the things that are available there. Again, e.g., any CommonJS module written in C++ will not work in the browser, with or without Browserify.

Finally, Browserify uses several modules that are basically API-compatible to Node.js, but have been rewritten for the browser, e.g. http-browserify.

So, in the end, it is a great tool for so-called "isomorphic JavaScript", or in other words: To use CommonJS modules on the server and in the browser without the need for special patterns on either side, such as AMD or UMD.

But, of course, it does not provide any magic :-)

Answer 2

Browserify doesn't add functionality to your browser. It compiles your Node.js code so that it is runnable inside of a browser.

In short, Browserify allows you to use Node's require in your browser-side code; it does not grant your browser access to network and filesystem abilities that it doesn't already have.

Instead, you'll need to use (or write) custom modules that simulate the server-side capabilities. For example, if you use a database module in your server-side code (e.g., Postgres or Mongo), you could write a new database module (with the same API as the server-side module) that uses browser-supported storage mechanisms like IndexedDB.